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Sample records for warm magnetized atomic

  1. Gradient Echo Quantum Memory in Warm Atomic Vapor

    PubMed Central

    Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M.; Everett, Jesse L.; Higginbottom, Daniel; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

    2013-01-01

    Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain. PMID:24300586

  2. Magnetic Control of Atomic Motion

    NASA Astrophysics Data System (ADS)

    Mazur, Tom; Bannerman, Travis; Chavez, Isaac; Clark, Rob; Libson, Adam; Raizen, Mark

    2010-03-01

    Using a sequence of pulsed electromagnetic coils, known as the atomic coilgun, we slowed supersonic beams of atomic neon and molecular oxygen. We report our progress toward adapting the atomic coilgun for magnetically trapping hydrogen isotopes. This work has motivated us to investigate other methods for magnetic control of atomic motion. We describe these techniques, and present calculations suggesting their utility in controlling atomic motion. We then outline our plans for using these methods in certain applications.

  3. Magnetic remanence in single atoms.

    PubMed

    Donati, F; Rusponi, S; Stepanow, S; Wäckerlin, C; Singha, A; Persichetti, L; Baltic, R; Diller, K; Patthey, F; Fernandes, E; Dreiser, J; Šljivančanin, Ž; Kummer, K; Nistor, C; Gambardella, P; Brune, H

    2016-04-15

    A permanent magnet retains a substantial fraction of its saturation magnetization in the absence of an external magnetic field. Realizing magnetic remanence in a single atom allows for storing and processing information in the smallest unit of matter. We show that individual holmium (Ho) atoms adsorbed on ultrathin MgO(100) layers on Ag(100) exhibit magnetic remanence up to a temperature of 30 kelvin and a relaxation time of 1500 seconds at 10 kelvin. This extraordinary stability is achieved by the realization of a symmetry-protected magnetic ground state and by decoupling the Ho spin from the underlying metal by a tunnel barrier. PMID:27081065

  4. Mass loss from warm giants: Magnetic effects

    NASA Technical Reports Server (NTRS)

    Mullan, D. J.

    1980-01-01

    Among warm giant stars, rapid mass loss sets in along a well defined velocity dividing line (VDL). Hot corona also disappear close to the VDL and thermal pressure cannot drive the observed rapid mass loss in these stars. The VDL may be associated with magnetic fields changing from closed to open. Such a change is consistent with the lack of X-rays from late-type giants. A magnetic transition locus based on Pneuman's work on helmet streamer stability agrees well with the empirical VDL. The change from closed to open fields not only makes rapid mass loss possible, but also contributes to energizing the mass loss in the form of discrete bubbles.

  5. The first single atom magnet

    NASA Astrophysics Data System (ADS)

    Donati, Fabio; Rusponi, Stefano; Wäckerlin, Christian; Singha, Aparajita; Baltic, Romana; Diller, Katharina; Patthey, François; Fernandes, Edgar; Brune, Harald; Dreiser, Jan; Sljivancanin, Zeljko; Kummer, Kurt; Stepanow, Sebastian; Persichetti, Luca; Nistor, Corneliu; Gambardella, Pietro

    The prime feature of a magnet is to retain a significant fraction of its saturation magnetization in the absence of an external magnetic field. Realizing magnetic remanence in a single atom would allow storing and processing information in the smallest unit of matter. Here we show that individual rare-earth atoms on ultrathin insulating layers grown on non-magnetic metal substrates exhibit magnetic remanence and, therefore, are the first magnets formed by a single surface adsorbed atom. These magnets have a magnetic lifetime of 1500 s and a coercive field of 3.7 T at 10 K. In addition, their hysteresis loop remains open up to 30 K. This first example of a single atom magnet shows bistability at a temperature which is significantly higher than the best single molecule magnets reported so far. Its extraordinary stability is achieved by a suitable combination of magnetic ground state and adsorption site symmetry, and by decoupling the 4 f spin from the underlying metal by a tunnel barrier.

  6. Magnetic trap for thulium atoms

    SciTech Connect

    Sukachev, D D; Sokolov, A V; Chebakov, K A; Akimov, A V; Kolachevskii, N N; Sorokin, Vadim N

    2011-08-31

    For the first time ultra-cold thulium atoms were trapped in a magnetic quadrupole trap with a small field gradient (20 Gs cm{sup -1}). The atoms were loaded from a cloud containing 4x10{sup 5} atoms that were preliminarily cooled in a magneto-optical trap to the sub-Doppler temperature of 80 {mu}K. As many as 4x10{sup 4} atoms were trapped in the magnetic trap at the temperature of 40 {mu}K. By the character of trap population decay the lifetime of atoms was determined (0.5 s) and an upper estimate was obtained for the rate constant of inelastic binary collisions for spin-polarised thulium atoms in the ground state (g{sub in} < 10{sup -11}cm{sup 3} s{sup -1}). (magnetic traps)

  7. Magnetic fusion development for global warming suppression

    NASA Astrophysics Data System (ADS)

    Li, Jiangang; Zhang, Jie; Duan, Xuru

    2010-01-01

    Energy shortage and environmental pollution are two critical issues for human beings in the 21st century. There is an urgent need for new sustainable energy to meet the fast growing demand for clean energy. Fusion is one of the few options which may be able to satisfy the requirement for large scale sustainable energy generation and global warming suppression and therefore must be developed as quickly as possible. Fusion research has been carried out for the past 50 years. It is too long to wait for another 50 years to generate electricity by fusion. A much more aggressive approach should be taken with international collaboration towards the early use of fusion energy to meet the urgent needs for energy and global warming suppression.

  8. Atomic and optical properties of warm dense copper

    NASA Astrophysics Data System (ADS)

    Miloshevsky, Gennady; Hassanein, Ahmed

    2015-09-01

    The emission of x rays from warm dense matter is of great interest for both spectroscopic diagnostics and development of intense x-ray sources. We report the results from the collisional-radiative steady-state (CRSS) modeling of atomic and optical properties of copper plasmas at near-solid and solid-state density for a range of temperatures. The CRSS model is validated against the available data on the average charge state and shifts of energy levels in aluminum and the opacity and emissivity spectra of carbon and aluminum plasmas. The average charge states, number density of ion species, and free electrons as a function of temperature are investigated for the solid-density copper plasma. Due to the dense plasma environment the four outer electrons are found to be unbounded even in the low-temperature limit ˜1 eV . As the temperature changes from 1 to 100 eV, the predominant species vary from fivefold- to twelvefold-ionized copper ions. The opacity and emissivity spectra of dense copper plasmas are studied using the local thermodynamic equilibrium (LTE) and non-LTE approaches. It is found that the non-LTE effects are important in the spectral region of soft x rays emitted from the K shell. The emissivity in spectral lines is completely suppressed, indicating the importance of the energy-dissipating radiative processes in this soft x-ray region. Line broadening and redshifts of the K - and L -shell spectral lines toward higher wavelengths are observed with the increase of plasma density. These results have important implications for understanding the radiative properties of warm dense copper and can be useful for future experimental studies.

  9. Atomic and optical properties of warm dense copper.

    PubMed

    Miloshevsky, Gennady; Hassanein, Ahmed

    2015-09-01

    The emission of x rays from warm dense matter is of great interest for both spectroscopic diagnostics and development of intense x-ray sources. We report the results from the collisional-radiative steady-state (CRSS) modeling of atomic and optical properties of copper plasmas at near-solid and solid-state density for a range of temperatures. The CRSS model is validated against the available data on the average charge state and shifts of energy levels in aluminum and the opacity and emissivity spectra of carbon and aluminum plasmas. The average charge states, number density of ion species, and free electrons as a function of temperature are investigated for the solid-density copper plasma. Due to the dense plasma environment the four outer electrons are found to be unbounded even in the low-temperature limit ∼1eV. As the temperature changes from 1 to 100 eV, the predominant species vary from fivefold- to twelvefold-ionized copper ions. The opacity and emissivity spectra of dense copper plasmas are studied using the local thermodynamic equilibrium (LTE) and non-LTE approaches. It is found that the non-LTE effects are important in the spectral region of soft x rays emitted from the K shell. The emissivity in spectral lines is completely suppressed, indicating the importance of the energy-dissipating radiative processes in this soft x-ray region. Line broadening and redshifts of the K- and L-shell spectral lines toward higher wavelengths are observed with the increase of plasma density. These results have important implications for understanding the radiative properties of warm dense copper and can be useful for future experimental studies. PMID:26465577

  10. Warm inflation in the presence of magnetic fields

    NASA Astrophysics Data System (ADS)

    Piccinelli, Gabriella; Sánchez, Ángel; Ayala, Alejandro; Mizher, Ana Julia

    2014-10-01

    We study the effects of primordial magnetic fields on the inflationary potential in the context of a warm inflation scenario. The model, based on global supersymmetry with a new-inflation-type potential and a coupling between the inflaton and a heavy intermediate superfield, is already known to preserve the flatness required for slow-roll conditions even after including thermal contributions. Here we show that the magnetic field makes the potential even flatter, retarding the transition and rendering it smoother.

  11. Topological Superconductivity with Magnetic Atoms

    NASA Astrophysics Data System (ADS)

    Glazman, Leonid

    2015-03-01

    Chains of magnetic impurities embedded in a conventional s-wave superconductor may induce the formation of a topologically non-trivial superconducting phase. If such a phase is formed along a chain, then its ends carry Majorana fermions. We investigate this possibility theoretically by developing a tight-binding Bogoliubov-de Gennes description, starting from the Shiba bound states induced by the individual magnetic impurities. While the resulting Hamiltonian has similarities with the Kitaev model for one-dimensional spinless p-wave superconductors, there are also important differences, most notably the long-range (power-law) nature of hopping and pairing as well as the complex hopping amplitudes. We develop an analytical theory, complemented by numerical approaches, which accounts for the electron long-range pairing and hopping along the chain, inhomogeneous magnetic order in the chain of embedded impurities or spin-orbit coupling in the host superconductor, and the possibility of direct electron hopping between the impurity atoms. This allows us to elucidate the domain of parameters favoring the formation of a topological phase and to find the spatial structure of Majorana states appearing in that phase. This talk is based on joint work with F. von Oppen, Falko Pientka, and Yang Peng.

  12. Surface electromagnetic wave equations in a warm magnetized quantum plasma

    SciTech Connect

    Li, Chunhua; Yang, Weihong; Wu, Zhengwei; Chu, Paul K.

    2014-07-15

    Based on the single-fluid plasma model, a theoretical investigation of surface electromagnetic waves in a warm quantum magnetized inhomogeneous plasma is presented. The surface electromagnetic waves are assumed to propagate on the plane between a vacuum and a warm quantum magnetized plasma. The quantum magnetohydrodynamic model includes quantum diffraction effect (Bohm potential), and quantum statistical pressure is used to derive the new dispersion relation of surface electromagnetic waves. And the general dispersion relation is analyzed in some special cases of interest. It is shown that surface plasma oscillations can be propagated due to quantum effects, and the propagation velocity is enhanced. Furthermore, the external magnetic field has a significant effect on surface wave's dispersion equation. Our work should be of a useful tool for investigating the physical characteristic of surface waves and physical properties of the bounded quantum plasmas.

  13. Warm and dense stellar matter under strong magnetic fields

    SciTech Connect

    Rabhi, A.; Panda, P. K.; Providencia, C.

    2011-09-15

    We investigate the effects of strong magnetic fields on the equation of state of warm stellar matter as it may occur in a protoneutron star. Both neutrino-free and neutrino-trapped matter at a fixed entropy per baryon are analyzed. A relativistic mean-field nuclear model, including the possibility of hyperon formation, is considered. A density-dependent magnetic field with a magnitude of 10{sup 15} G at the surface and not more than 3x10{sup 18} G at the center is considered. The magnetic field gives rise to a neutrino suppression, mainly at low densities, in matter with trapped neutrinos. It is shown that a hybrid protoneutron star will not evolve into a low-mass black hole if the magnetic field is strong enough and the magnetic field does not decay. However, the decay of the magnetic field after cooling may give rise to the formation of a low-mass black hole.

  14. Warm Magnetic Field Measurements of LARP HQ Magnet

    SciTech Connect

    Caspi, S; Cheng, D; Deitderich, D; Felice, H; Ferracin, P; Hafalia, R; Joseph, J; Lizarazo, J; Martchevskii, M; Nash, C; Sabbi, G L; Vu, C; Schmalzle, J; Ambrosio, G; Bossert, R; Chlachidze, G; DiMarco, J; Kashikhin, V

    2011-03-28

    The US-LHC Accelerator Research Program is developing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of Nb{sub 3}Sn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such as alignment and field quality. Here we present the magnetic measurement results obtained at LBNL with a constant current of 30 A. A 100 mm long circuit-board rotating coil developed by FNAL was used and the induced voltage and flux increment were acquired. The measured b{sub 6} ranges from 0.3 to 0.5 units in the magnet straight section at a reference radius of 21.55 mm. The data reduced from the numerical integration of the raw voltage agree with those from the fast digital integrators.

  15. Magnetic trapping of circular Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Anderson, David; Schwarzkopf, Andrew; Raithel, Georg

    2013-05-01

    Circular Rydberg atoms exhibit a unique combination of properties: long lifetimes ( n5), large magnetic moments and angular momenta (|m | = l =n - 1), and no first order Stark shift. Here, n , l and m are the principal, orbital and magnetic quantum numbers, respectively. Several of these features have made circular Rydberg atoms attractive for a number of applications including photon-atom interaction and Rydberg interaction experiments. We present here the realization of a magnetic trap for circular Rydberg atoms. The Rydberg-atom trap is characterized using state-selective electric-field ionization, direct spatial imaging of the atom distributions and time-of-flight analysis of the ion signal. At room temperature, we observe 70 percent of the trapped atoms remaining after 6ms. We measure an increase of the center-of-mass trap oscillation frequency by the expected factor of √{ | m | }. Simulations of the state-evolution of circular-state atoms in our magnetic trap, held at 300K radiation temperature, are performed and results are in good agreement with the observed phenomena. This work was supported by the AFOSR (FA9550-10-1-0453).

  16. Ladder-type electromagnetically induced transparency using nanofiber-guided light in a warm atomic vapor

    NASA Astrophysics Data System (ADS)

    Jones, D. E.; Franson, J. D.; Pittman, T. B.

    2015-10-01

    We demonstrate ladder-type electromagnetically induced transparency (EIT) using an optical nanofiber suspended in a warm rubidium vapor. The signal and control fields are both guided along the nanofiber, which enables strong nonlinear interactions with the surrounding atoms at relatively low powers. Transit-time broadening is found to be a significant EIT decoherence mechanism in this tightly confined waveguiding geometry. Nonetheless, we observe significant EIT and controlled polarization rotation using control-field powers of only a few microwatts in this relatively robust warm-atom nanofiber system.

  17. Analysis of a magnetically trapped atom clock

    SciTech Connect

    Kadio, D.; Band, Y. B.

    2006-11-15

    We consider optimization of a rubidium atom clock that uses magnetically trapped Bose condensed atoms in a highly elongated trap, and determine the optimal conditions for minimum Allan variance of the clock using microwave Ramsey fringe spectroscopy. Elimination of magnetic field shifts and collisional shifts are considered. The effects of spin-dipolar relaxation are addressed in the optimization of the clock. We find that for the interstate interaction strength equal to or larger than the intrastate interaction strengths, a modulational instability results in phase separation and symmetry breaking of the two-component condensate composed of the ground and excited hyperfine clock levels, and this mechanism limits the clock accuracy.

  18. Atomization methods for forming magnet powders

    DOEpatents

    Sellers, Charles H.; Branagan, Daniel J.; Hyde, Timothy A.

    2000-01-01

    The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: a) forming a melt comprising R.sub.2.1 Q.sub.13.9 B.sub.1, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R.sub.2.1 Q.sub.13.9 B.sub.1.

  19. Zeeman relaxation of magnetically trapped Eu atoms

    SciTech Connect

    Suleimanov, Yury V.

    2010-02-15

    We perform rigorous quantum mechanical calculations for collisions between magnetically trapped Eu atoms to elucidate the results of recent experimental studies. We show that the relaxation from the maximally stretched m{sub s}=7/2 level is entirely determined by the magnetic dipole-dipole interaction and analyze the role of the electronic spin-exchange interaction in transitions from the lower-energy Zeeman levels. The relaxation of the m{sub s}=5/2 state is shown to be very sensitive to the spin-exchange parameter that determines the splitting between the lowest electronic states of the Eu dimer. We suggest that cold collision experiments with trapped atoms can be used as a tool for obtaining accurate information on the electronic spin anisotropy in complex molecules such as Eu{sub 2}.

  20. Atomic Calculations and Laboratory Measurements Relevant to X-ray Warm Absorbers

    NASA Technical Reports Server (NTRS)

    Kallman, Tim; Bautista, M.; Palmeri, P.

    2007-01-01

    This viewgraph document reviews the atomic calculations and the measurements from the laboratory that are relevant to our understanding of X-Ray Warm Absorbers. Included is a brief discussion of the theoretical and the experimental tools. Also included is a discussion of the challenges, and calculations relevant to dielectronic recombination, photoionization cross sections, and collisional ionization. A review of the models is included, and the sequence that the models were applied.

  1. Development of a Superconducting Magnet System for the ONR/General Atomics Homopolar Motor

    NASA Astrophysics Data System (ADS)

    Schaubel, K. M.; Langhorn, A. R.; Creedon, W. P.; Johanson, N. W.; Sheynin, S.; Thome, R. J.

    2006-04-01

    This paper describes the design, testing and operational experience of a superconducting magnet system presently in use on the Homopolar Motor Program. The homopolar motor is presently being tested at General Atomics in San Diego, California for the U.S Navy Office of Naval Research. The magnet system consists of two identical superconducting solenoid coils housed in two cryostats mounted integrally within the homopolar motor housing. The coils provide the static magnetic field required for motor operation and are wound using NbTi superconductor in a copper matrix. Each magnet is conduction cooled using a Gifford McMahon cryocooler. The coils are in close proximity to the iron motor housing requiring a cold to warm support structure with high stiffness and strength. The design of the coils, cold to warm support structure, cryogenic system, and the overall magnet system design will be described. The test results and operational experience will also be described.

  2. Atomic scale evolution of magnetic anisotropies

    NASA Astrophysics Data System (ADS)

    Bland, J. A. C.; Hope, S.; Tselepi, M.; Choi, B.

    1998-03-01

    The results of in situ studies of the evolution of the magnetic anisotropy of Co(100) and Co(110) epitaxial films are discussed. It is shown that uniaxial magnetic anisotropies are the generic signature of symmetry breaking atomic and nm scale structures, e.g. steps, clusters, islands revealed by scanning tunnelling microscopy (STM) studies, and are strongly affected by nonmagnetic overlayers. However, the thickness dependent behaviour is surprisingly complex, with strong changes in anisotropy behaviour occurring with submonolayer depositions of nonmagnetic overlayers. These effects cannot be understood within the usual framework of the Nel model but are discussed in terms of several contributing mechanisms, e.g. strain, dipolar interactions and edge and surface anisotropies.

  3. Tailoring the chiral magnetic interaction between two individual atoms.

    PubMed

    Khajetoorians, A A; Steinbrecher, M; Ternes, M; Bouhassoune, M; Dos Santos Dias, M; Lounis, S; Wiebe, J; Wiesendanger, R

    2016-01-01

    Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets. PMID:26902332

  4. Tailoring the chiral magnetic interaction between two individual atoms

    NASA Astrophysics Data System (ADS)

    Khajetoorians, A. A.; Steinbrecher, M.; Ternes, M.; Bouhassoune, M.; Dos Santos Dias, M.; Lounis, S.; Wiebe, J.; Wiesendanger, R.

    2016-02-01

    Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets.

  5. Tailoring the chiral magnetic interaction between two individual atoms

    PubMed Central

    Khajetoorians, A. A.; Steinbrecher, M.; Ternes, M.; Bouhassoune, M.; dos Santos Dias, M.; Lounis, S.; Wiebe, J.; Wiesendanger, R.

    2016-01-01

    Chiral magnets are a promising route towards dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii–Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron-mediated Dzyaloshinskii–Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunnelling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets. PMID:26902332

  6. Hydrogen atom in intense magnetic field.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Kelly, D. C.

    1972-01-01

    The structure of a hydrogen atom situated in an intense magnetic field is investigaged. Three approaches are employed. An elementary Bohr picture establishes a crucial magnetic field strength, H sub a approximately equal to 5 x 10 to the 9th G. Fields in excess of H sub a are intense in that they are able to modify the characteristic atomic scales of length and binding energy. A second approach solves the Schrodinger equation by a combination of variational methods and perturbation theory. It yields analytic expressions for the wave functions and energy eigenvalues. A third approach determines the energy eigenvalues by reducing the Schrodinger equation to a one-dimensional wave equation, which is then solved numerically. Energy eigenvalues are tabulated for field strengths of 2 x 10 to the 10th G and 2 x 10 to the 12th G. It is found that at 2 x 10 to the 12th G the lowest energy eigenvalue is changed from -13.6 to about -180 eV in agreement with previous variational computations.

  7. Magnetization of a warm plasma by the nonstationary ponderomotive force of an electromagnetic wave

    SciTech Connect

    Shukla, Nitin; Shukla, P. K.; Stenflo, L.

    2009-08-15

    It is shown that magnetic fields can be generated in a warm plasma by the nonstationary ponderomotive force of a large-amplitude electromagnetic wave. In the present Brief Report, we derive simple and explicit results that can be useful for understanding the origin of the magnetic fields that are produced in intense laser-plasma interaction experiments.

  8. Observation of Magnetically Induced Trap Loss of Ultracold Thulium Atoms

    NASA Astrophysics Data System (ADS)

    Kalganova, E. S.; Vishnyakova, G. A.; Golovizin, A. A.; Tregubov, D. O.; Sukachev, D. D.; Akimov, A. V.; Kolachevsky, N. N.; Khabarova, K. Yu.; Sorokin, V. N.

    2015-09-01

    We report the observation of influence of homogeneous magnetic field on an optical lattice losses of ultracold thulium atoms. The atomic cloud temperature was T = 15 mK. The dependence of trap population on a value of magnetic field has a broad resonance in the low-field region with a center at B = 0.4 G. We also have measured a decrease of optical lattice lifetime in a presence of resonance magnetic field. The observed magnetically-induced trap losses are assumed to be Feshbach resonance which is a dependence of an atomic scattering length on magnetic field.

  9. Atomic-scale control of graphene magnetism by using hydrogen atoms.

    PubMed

    González-Herrero, Héctor; Gómez-Rodríguez, José M; Mallet, Pierre; Moaied, Mohamed; Palacios, Juan José; Salgado, Carlos; Ugeda, Miguel M; Veuillen, Jean-Yves; Yndurain, Félix; Brihuega, Iván

    2016-04-22

    Isolated hydrogen atoms absorbed on graphene are predicted to induce magnetic moments. Here we demonstrate that the adsorption of a single hydrogen atom on graphene induces a magnetic moment characterized by a ~20-millielectron volt spin-split state at the Fermi energy. Our scanning tunneling microscopy (STM) experiments, complemented by first-principles calculations, show that such a spin-polarized state is essentially localized on the carbon sublattice opposite to the one where the hydrogen atom is chemisorbed. This atomically modulated spin texture, which extends several nanometers away from the hydrogen atom, drives the direct coupling between the magnetic moments at unusually long distances. By using the STM tip to manipulate hydrogen atoms with atomic precision, it is possible to tailor the magnetism of selected graphene regions. PMID:27102478

  10. Atomic hydrogen storage. [cryotrapping and magnetic field strength

    NASA Technical Reports Server (NTRS)

    Woollam, J. A. (Inventor)

    1980-01-01

    Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

  11. Quantum molecular dynamics study of expanded beryllium: Evolution from warm dense matter to atomic fluid

    PubMed Central

    Li, Dafang; Liu, Haitao; Zeng, Siliang; Wang, Cong; Wu, Zeqing; Zhang, Ping; Yan, Jun

    2014-01-01

    By performing quantum molecular dynamics (QMD) simulations, we investigate the equation of states, electrical and optical properties of the expanded beryllium at densities two to one-hundred lower than the normal solid density, and temperatures ranging from 5000 to 30000 K. With decreasing the density of Be, the optical response evolves from the one characteristic of a simple metal to the one of an atomic fluid. By fitting the optical conductivity spectra with the Drude-Smith model, it is found that the conducting electrons become localized at lower densities. In addition, the negative derivative of the electrical resistivity on temperature at density about eight lower than the normal solid density demonstrates that the metal to nonmetal transition takes place in the expanded Be. To interpret this transition, the electronic density of states is analyzed systematically. Furthermore, a direct comparison of the Rosseland opacity obtained by using QMD and the standard opacity code demonstrates that QMD provides a powerful tool to validate plasma models used in atomic physics approaches in the warm dense matter regime. PMID:25081816

  12. Dynamical Generation of Topological Magnetic Lattices for Ultracold Atoms

    NASA Astrophysics Data System (ADS)

    Yu, Jinlong; Xu, Zhi-Fang; Lü, Rong; You, Li

    2016-04-01

    We propose a scheme to dynamically synthesize a space-periodic effective magnetic field for neutral atoms by time-periodic magnetic field pulses. When atomic spin adiabatically follows the direction of the effective magnetic field, an adiabatic scalar potential together with a geometric vector potential emerges for the atomic center-of-mass motion, due to the Berry phase effect. While atoms hop between honeycomb lattice sites formed by the minima of the adiabatic potential, complex Peierls phase factors in the hopping coefficients are induced by the vector potential, and these phase factors facilitate a topological Chern insulator. With further tuning of external parameters, both a topological phase transition and topological flat bands can be achieved, highlighting realistic prospects for studying strongly correlated phenomena in this system. Our Letter presents an alternative pathway towards creating and manipulating topological states of ultracold atoms by magnetic fields.

  13. Dynamical Generation of Topological Magnetic Lattices for Ultracold Atoms.

    PubMed

    Yu, Jinlong; Xu, Zhi-Fang; Lü, Rong; You, Li

    2016-04-01

    We propose a scheme to dynamically synthesize a space-periodic effective magnetic field for neutral atoms by time-periodic magnetic field pulses. When atomic spin adiabatically follows the direction of the effective magnetic field, an adiabatic scalar potential together with a geometric vector potential emerges for the atomic center-of-mass motion, due to the Berry phase effect. While atoms hop between honeycomb lattice sites formed by the minima of the adiabatic potential, complex Peierls phase factors in the hopping coefficients are induced by the vector potential, and these phase factors facilitate a topological Chern insulator. With further tuning of external parameters, both a topological phase transition and topological flat bands can be achieved, highlighting realistic prospects for studying strongly correlated phenomena in this system. Our Letter presents an alternative pathway towards creating and manipulating topological states of ultracold atoms by magnetic fields. PMID:27104703

  14. Wave breaking of nonlinear electron oscillations in a warm magnetized plasma

    SciTech Connect

    Pramanik, Sourav; Maity, Chandan; Chakrabarti, Nikhil

    2014-02-15

    Wave breaking phenomena of nonlinear electron oscillations around a homogeneous background of massive ions have been studied in a warm magnetized plasma by using Lagrangian variables. An inhomogeneity in the background magnetic field is shown to induce phase mixing and thus breaking of the oscillations. A nonlinear analysis in Lagrangian variables predicts that wave breaking may disappear above a critical value of the electron temperature. An estimate for the critical temperature has been provided.

  15. Manipulating Neutral Atoms in Chip-Based Magnetic Traps

    NASA Technical Reports Server (NTRS)

    Aveline, David; Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Yu, Nan; Kohel, James

    2009-01-01

    Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides. The basic principle of these techniques is to control gradient magnetic fields with suitable timing so as to alter a trap to exert position-, velocity-, and/or time-dependent forces on atoms in the trap to obtain desired effects. The trap magnetic fields are generated by controlled electric currents flowing in both macroscopic off-chip electromagnet coils and microscopic wires on the surface of the chip. The methods are best explained in terms of examples. Rather than simply allowing atoms to expand freely into an atomic waveguide, one can give them a controllable push by switching on an externally generated or a chip-based gradient magnetic field. This push can increase the speed of the atoms, typically from about 5 to about 20 cm/s. Applying a non-linear magnetic-field gradient exerts different forces on atoms in different positions a phenomenon that one can exploit by introducing a delay between releasing atoms into the waveguide and turning on the magnetic field.

  16. Atomic beam focusing with a curved magnetic mirror

    NASA Astrophysics Data System (ADS)

    Merimeche, H.

    2006-09-01

    Reflective atom optics has been experimentally realized with a continuous flux of cold atoms by using a magnetized videotape. We have studied the behaviour of a slow atomic beam with a velocity of 20 m s-1 incident at different angles on the surface of a curved magnetic mirror. Focusing of the beam has been demonstrated and this induces an amplification up to a factor 3 of the fluorescence emitted by the atoms around the focal point. We deduced the shape of our reflector from the focal length measurements and show that the result is completely consistent with those obtained from the reflection of a red diode laser beam on the curved mirror.

  17. Induce magnetism into silicene by embedding transition-metal atoms

    SciTech Connect

    Sun, Xiaotian; Wang, Lu E-mail: yyli@suda.edu.cn; Lin, Haiping; Hou, Tingjun; Li, Youyong E-mail: yyli@suda.edu.cn

    2015-06-01

    Embedding transition-metal (TM) atoms into nonmagnetic nanomaterials is an efficient way to induce magnetism. Using first-principles calculations, we systematically investigated the structural stability and magnetic properties of TM atoms from Sc to Zn embedded into silicene with single vacancy (SV) and double vacancies (DV). The binding energies for different TM atoms correlate with the TM d-shell electrons. Sc, Ti, and Co show the largest binding energies of as high as 6 eV, while Zn has the lowest binding energy of about 2 eV. The magnetic moment of silicene can be modulated by embedding TM atoms from V to Co, which mainly comes from the 3d orbitals of TM along with partly contributions from the neighboring Si atoms. Fe atom on SV and Mn atom on DV have the largest magnetic moment of more than 3 μB. In addition, we find that doping of N or C atoms on the vacancy site could greatly enhance the magnetism of the systems. Our results provide a promising approach to design silicene-based nanoelectronics and spintronics device.

  18. Tailoring the chiral magnetic interaction between two individual atoms

    NASA Astrophysics Data System (ADS)

    Wiebe, J.; Khajetoorians, A. A.; Steinbrecher, M.; Ternes, M.; Bouhassoune, M.; Dos Santos Dias, M.; Lounis, S.; Wiesendanger, R.

    Chiral magnets are a promising route toward dense magnetic storage technology due to their inherent nano-scale dimensions and energy efficient properties. Engineering chiral magnets requires atomic-level control of the magnetic exchange interactions, including the Dzyaloshinskii-Moriya interaction, which defines a rotational sense for the magnetization of two coupled magnetic moments. Here we show that the indirect conduction electron mediated Dzyaloshinskii-Moriya interaction between two individual magnetic atoms on a metallic surface can be manipulated by changing the interatomic distance with the tip of a scanning tunneling microscope. We quantify this interaction by comparing our measurements to a quantum magnetic model and ab-initio calculations yielding a map of the chiral ground states of pairs of atoms depending on the interatomic separation. The map enables tailoring the chirality of the magnetization in dilute atomic-scale magnets. Acknowledgements: SFB668, GrK1286, SFB767, LO 1659 5-1, Emmy Noether Program of the DFG, FOM of NWO, VH-NG-717.

  19. Estimation of fluctuating magnetic fields by an atomic magnetometer

    SciTech Connect

    Petersen, Vivi; Moelmer, Klaus

    2006-10-15

    We present a theoretical procedure to estimate with an atomic magnetometer the time dependence of a magnetic field that fluctuates according to an Ornstein-Uhlenbeck process. The magnetometer applies the detected polarization rotation of an optical probe to measure a collective atomic spin, which precesses due to the magnetic field. Based on the noisy optical detection record, our consistent Gaussian update formalism provides an estimator for the magnetic fields, and we identify analytically the steady-state performance of this estimator. We show that the estimate of the current value of the magnetic field is further improved if noisy measurement data obtained also at later times are taken into account.

  20. Production and detection of atomic hexadecapole at Earth's magnetic field.

    PubMed

    Acosta, V M; Auzinsh, M; Gawlik, W; Grisins, P; Higbie, J M; Jackson Kimball, D F; Krzemien, L; Ledbetter, M P; Pustelny, S; Rochester, S M; Yashchuk, V V; Budker, D

    2008-07-21

    Optical magnetometers measure magnetic fields with extremely high precision and without cryogenics. However, at geomagnetic fields, important for applications from landmine removal to archaeology, they suffer from nonlinear Zeeman splitting, leading to systematic dependence on sensor orientation. We present experimental results on a method of eliminating this systematic error, using the hexadecapole atomic polarization moment. In particular, we demonstrate selective production of the atomic hexadecapole moment at Earth's magnetic field and verify its immunity to nonlinear Zeeman splitting. This technique promises to eliminate directional errors in all-optical atomic magnetometers, potentially improving their measurement accuracy by several orders of magnitude. PMID:18648462

  1. Atomic spin orbit coupling synthesized with gradient magnetic fields

    NASA Astrophysics Data System (ADS)

    Luo, Xinyu; Wu, Lingna; Wang, Ruquan; You, L.

    2015-09-01

    Spin orbit coupling (SOC) for neutral atoms can be synthesized with pulsed or time modulating gradient magnetic field (GMF). This is confirmed through the studies of collective dipole oscillations for a spin-1 atomic condensate in a harmonic trap after abruptly turning on SOC and adiabatically adjusted equilibrium states when SOC strength is slowly ramped up. Further measurements reveal that SOC can be enhanced when the GMF modulation frequency approaches harmonic trap frequency. Additionally, we discuss how the technique of pulsed GMF can be used to synthesize space-period magnetic fields, or magnetic lattices.

  2. A two-dimensional permanent magnetic lattice for ultracold atoms

    NASA Astrophysics Data System (ADS)

    Mohammadi, Amir; Ghanbari, Saeed; Pariz, Aref

    2013-07-01

    We propose a permanent magnetic lattice for creating a two-dimensional array of Ioffe-Pritchard permanent magnetic microtraps for holding and controlling ultracold atoms and Bose-Einstein condensates. This atom chip may be fabricated using laser carving on two separate magnetic films such as Tb6Gd10Fe80Co4 with thicknesses of 500 and 50 nm, respectively, and a periodicity of 1 μm. The trap depth and frequencies are controlled via an external bias field to handle tunneling rates between lattice sites. We present analytical expressions and compare them with numerical calculations.

  3. Emerging magnetic order in platinum atomic contacts and chains

    PubMed Central

    Strigl, Florian; Espy, Christopher; Bückle, Maximilian; Scheer, Elke; Pietsch, Torsten

    2015-01-01

    The development of atomic-scale structures revealing novel transport phenomena is a major goal of nanotechnology. Examples include chains of atoms that form while stretching a transition metal contact or the predicted formation of magnetic order in these chains, the existence of which is still debated. Here we report an experimental study of the magneto-conductance (MC) and anisotropic MC with atomic-size contacts and mono-atomic chains of the nonmagnetic metal platinum. We find a pronounced and diverse MC behaviour, the amplitude and functional dependence change when stretching the contact by subatomic distances. These findings can be interpreted as a signature of local magnetic order in the chain, which may be of particular importance for the application of atomic-sized contacts in spintronic devices of the smallest possible size. PMID:25649440

  4. Mesospheric Temperature and Atomic Oxygen Response during the January 2009 Major Stratospheric Warming

    NASA Astrophysics Data System (ADS)

    Shepherd, Marianna; Shepherd, Gordon; Cho, Young-Min; Ward, William E.; Drummond, James

    The study examines the response of the mesosphere/lower thermosphere to the major strato-spheric warming (SSW) event from January 2009, as seen in the OH and O2 (0,1) Atmospheric band airglow observations nominally at 87 km and 94 km, respectively by a SATI (Spectral Airglow Temperature Imager) instrument installed at the Polar Environment Atmospheric Re-search Laboratory (PEARL) at Eureka (80N, 86W) as part of the Canadian Network for the Detection of Atmospheric Change. At the time of the SSW the airglow emissions and the derived rotational temperatures appear depleted and decreased, followed by an enhancement of the airglow emission rates during the SSW recovery phase, while the temperatures returned to their pre-event state. An empirical relationship between OH airglow peak altitude determined by SABER and SATI integrated emission rates allowed perturbed OH and O2 (0,1) airglow altitudes to be assigned to the SATI observations. From these the O volume mixing ratio (VMR), corresponding to the observed OH and O2 (0,1) airglow emission rates were modeled. Atomic oxygen depletion by a factor of 5 was observed during the SSW and lasted for about 5 days. During the SSW recovery phase the O VMR giving rise to the observed O2 (0,1) airglow emission rates increased by a factor of 3.5 from its pre-SSW level and 17 times from the peak of the SSW. Perturbations in the OH and O2 (0,1) airglow layers with periods of 4-, 6-, 8-and 12-h indicate non-linear interaction between zonally symmetric semidiurnal tides and planetary waves.

  5. Mesospheric temperature and atomic oxygen response during the January 2009 major stratospheric warming

    NASA Astrophysics Data System (ADS)

    Shepherd, Marianna G.; Cho, Young-Min; Shepherd, Gordon G.; Ward, William; Drummond, James R.

    2010-07-01

    The study examines the response of the mesosphere/lower thermosphere to the major stratospheric warming (SSW) event from January 2009, as seen in the OH and O2(0,1) atmospheric band airglow observations nominally at 87 and 94 km, respectively, by a SATI (Spectral Airglow Temperature Imager) instrument installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka (80°N, 86°W) as part of the Canadian Network for the Detection of Atmospheric Change. At the time of the SSW, the airglow emissions and the derived rotational temperatures appear depleted and decreased, followed by an enhancement of the airglow emission rates during the SSW recovery phase, while the temperatures returned to their pre-event state. An empirical relationship between OH airglow peak altitude determined by SABER (Sounding of the Atmosphere by Broadband Emission Radiometry) and SATI integrated emission rates allowed perturbed OH and O2(0,1) airglow altitudes to be assigned to the SATI observations. From these, the O volume mixing ratio (VMR), corresponding to the observed OH and O2(0,1) airglow emission rates were modeled. Atomic oxygen depletion by a factor of ˜5 was observed during the SSW and lasted for about 5 days. During the SSW recovery phase, the O VMR giving rise to the observed O2(0,1) airglow emission rates increased by a factor of 3.5 from its pre-SSW level and 17 times from the peak of the SSW. Perturbations in the OH and O2(0,1) airglow layers with periods of 4, 6, 8, and 12 h indicate nonlinear interaction between zonally symmetric semidiurnal tides and planetary waves.

  6. B-spline algorithm for magnetized multielectron atomic structures

    NASA Astrophysics Data System (ADS)

    Zhao, L. B.; Stancil, P. C.

    2008-03-01

    A B-spline algorithm has been developed to evaluate the electronic structure of multielectron atoms in a magnetic field. A generalized electron configuration concept, which is crucial to perform the current investigation, was introduced to solve Hartree-Fock equations. The wave functions for electron orbitals of the magnetized multielectron atom are expanded in terms of a B-spline basis in the radial direction and spherical harmonics in the angular direction. The developed algorithm has been applied to calculations of He in a magnetic field. Energy levels of magnetized He in the ground state are presented as a function of magnetic field strength with a range from zero up to 2.35×107T and compared with available theoretical data.

  7. Magnetism and surface structure of atomically controlled ultrathin metal films.

    SciTech Connect

    Shiratsuchi, Yu.; Yamamoto, M.; Bader, S. D.; Materials Science Division; Osaka Univ.

    2007-01-01

    We review the correlation of magnetism and surface structure in ultrathin metal films, including the tailoring of novel magnetic properties using atomic scale control of the nanostructure. We provide an overview of modern fabrication and characterization techniques used to create and explore these fascinating materials, and highlight important phenomena of interest. We also discuss techniques that control and characterize both the magnetic and structural properties on an atomic scale. Recent advances in the development and applications of these techniques allow nanomagnetism to be investigated in an unprecedented manner. A system cannot necessarily retain a two-dimensional structure as it enters the ultrathin region, but it can transform into a three-dimensional, discontinuous structure due to the Volmer-Weber growth mechanism. This structural transformation can give rise to superparamagnetism. During this evolution, competing factors such as interparticle interactions and the effective magnetic anisotropy govern the magnetic state. These magnetic parameters are influenced by the nanostructure of the film. In particular, controlling the magnetic anisotropy is critical for determining the magnetic properties. Surface effects play especially important roles in influencing both the magnitude and direction of the magnetic anisotropy in ultrathin films. By properly altering the surface structure, the strength and direction of the magnetic anisotropy are controlled via spin-orbit and/or dipole interactions.

  8. Chemically induced magnetism in atomically precise gold clusters.

    PubMed

    Krishna, Katla Sai; Tarakeshwar, Pilarisetty; Mujica, Vladimiro; Kumar, Challa S S R

    2014-03-12

    Comparative theoretical and experimental investigations are reported into chemically induced magnetism in atomically-precise, ligand-stabilized gold clusters Au25 , Au38 and Au55 . The results indicate that [Au25 (PPh3 )10 (SC12 H25 )5 Cl2 ](2+) and Au38 (SC12 H25 )24 are diamagnetic, Au25 (SC2 H4 Ph)18 is paramagnetic, and Au55 (PPh3 )12 Cl6 , is ferromagnetic at room temperature. Understanding the magnetic properties resulting from quantum size effects in such atomically precise gold clusters could lead to new fundamental discoveries and applications. PMID:24150895

  9. Dynamical localization: Hydrogen atoms in magnetic and microwave fields

    SciTech Connect

    Benvenuto, F.; Casati, G.; Shepelyansky, D.L.

    1997-03-01

    We show that dynamical localization for excited hydrogen atoms in magnetic and microwave fields takes place at quite low microwave frequency ({omega}n{sup 3}{lt}1). Estimates of the localization length are given for different parameter regimes, showing that the quantum delocalization border drops significantly as compared to the case of zero magnetic field. This opens up broad possibilities for laboratory investigations. {copyright} {ital 1997} {ital The American Physical Society}

  10. Properties of a warm plasma collisional sheath in an oblique magnetic field

    SciTech Connect

    Ou Jing; Yang Jinhong

    2012-11-15

    The properties of a warm plasma collisional sheath in an oblique magnetic field and the associated sheath criterion are investigated with a two-fluid model. In the fluid framework, a sheath criterion including effects of the magnetic field and collision is established theoretically for a wide range of ion temperature. With the sheath criterion as the plasma-sheath boundary condition, different plasma parameters including potential, electron and ion densities, and ion velocity are calculated for various ion temperatures and ion thermal motions. It is shown that the properties of the sheath depend not only on the plasma balance equations but also on the sheath boundary conditions. In addition, effects of the directions and magnitudes of the magnetic field on the plasma sheath are also discussed under different ion temperatures.

  11. Ultracold Dipolar Molecules Composed of Strongly Magnetic Atoms

    NASA Astrophysics Data System (ADS)

    Frisch, A.; Mark, M.; Aikawa, K.; Baier, S.; Grimm, R.; Petrov, A.; Kotochigova, S.; Qumner, G.; Lepers, M.; Dulieu, O.; Ferlaino, F.

    2015-11-01

    In a combined experimental and theoretical effort, we demonstrate a novel type of dipolar system made of ultracold bosonic dipolar molecules with large magnetic dipole moments. Our dipolar molecules are formed in weakly bound Feshbach molecular states from a sample of strongly magnetic bosonic erbium atoms. We show that the ultracold magnetic molecules can carry very large dipole moments and we demonstrate how to create and characterize them, and how to change their orientation. Finally, we confirm that the relaxation rates of molecules in a quasi-two-dimensional geometry can be reduced by using the anisotropy of the dipole-dipole interaction and that this reduction follows a universal dipolar behavior.

  12. Reactions between NO/+/ and metal atoms using magnetically confined afterglows

    NASA Technical Reports Server (NTRS)

    Lo, H. H.; Clendenning, L. M.; Fite, W. L.

    1977-01-01

    A new method of studying thermal energy ion-neutral collision processes involving nongaseous neutral atoms is described. A long magnetic field produced by a solenoid in a vacuum chamber confines a thermal-energy plasma generated by photoionization of gas at very low pressure. As the plasma moves toward the end of the field, it is crossed by a metal atom beam. Ionic products of ion-atom reactions are trapped by the field and both the reactant and product ions move to the end of the magnetic field where they are detected by a quadrupole mass filter. The cross sections for charge transfer between NO(+) and Na, Mg, Ca, and Sr and that for rearrangement between NO(+) and Ca have been obtained. The charge-transfer reaction is found strongly dominant over the rearrangement reaction that forms metallic oxide ions.

  13. Average-atom treatment of relaxation time in x-ray Thomson scattering from warm dense matter

    NASA Astrophysics Data System (ADS)

    Johnson, W. R.; Nilsen, J.

    2016-03-01

    The influence of finite relaxation times on Thomson scattering from warm dense plasmas is examined within the framework of the average-atom approximation. Presently most calculations use the collision-free Lindhard dielectric function to evaluate the free-electron contribution to the Thomson cross section. In this work, we use the Mermin dielectric function, which includes relaxation time explicitly. The relaxation time is evaluated by treating the average atom as an impurity in a uniform electron gas and depends critically on the transport cross section. The calculated relaxation rates agree well with values inferred from the Ziman formula for the static conductivity and also with rates inferred from a fit to the frequency-dependent conductivity. Transport cross sections determined by the phase-shift analysis in the average-atom potential are compared with those evaluated in the commonly used Born approximation. The Born approximation converges to the exact cross sections at high energies; however, differences that occur at low energies lead to corresponding differences in relaxation rates. The relative importance of including relaxation time when modeling x-ray Thomson scattering spectra is examined by comparing calculations of the free-electron dynamic structure function for Thomson scattering using Lindhard and Mermin dielectric functions. Applications are given to warm dense Be plasmas, with temperatures ranging from 2 to 32 eV and densities ranging from 2 to 64 g/cc.

  14. Magnetic shielding of the cold atom space clock PHARAO

    NASA Astrophysics Data System (ADS)

    Moric, Igor; Laurent, Philippe; Chatard, Philippe; de Graeve, Charles-Marie; Thomin, Stephane; Christophe, Vincent; Grosjean, Olivier

    2014-09-01

    The space clock PHARAO is an atomic clock based on laser cooled cesium atoms. In order to attenuate magnetic field fluctuation in orbit, PHARAO clock uses three concentric Mumetal magnetic shields combined with several coils to improve the field homogeneity. We have characterized the attenuation and magnetic field homogeneity of the shields used to build the flight model. The average value of attenuation inside the three shields is around 18,000 when the external field is similar to the orbit field (30 μT) and the field homogeneity is lower than 10 nT. These values have not changed after vibrations and thermal tests for the space qualification. Permeability variation of the shields as a function of the intercepted flux has been analyzed.

  15. Pre- and postoperative magnetic resonance imaging in neonatal arterial switch operation using warm perfusion.

    PubMed

    Durandy, Yves; Rubatti, Marina; Couturier, Roland; Rohnean, Adela

    2011-11-01

    Neurological morbidity is a major concern in pediatric cardiac surgery. Cardiopulmonary bypass is one of the few modifiable factors affecting neurodevelopmental outcome. This study aimed to measure the incidence of abnormalities apparent by magnetic resonance imaging (MRI) after neonatal arterial switch operation using warm surgery. Neonates admitted for transposition of the great arteries underwent pre- and postoperative brain MRI. They were operated on using a warm perfusion method. The data collected included antenatal diagnosis, place of birth, gestational age, total maturation score as described by Childs, weight, cyanosis as assessed by minimal SpO(2) sustained for at least 10 min, balloon atrial septostomy, prostaglandin E1 infusion, need for neonatal intensive care, bypass time, time to extubation, and length of stay in intensive care. All of the MRI results were interpreted by the same senior specialist in pediatric neuroimaging, and lesions were classified as white matter injury, infarct, or hemorrhage. On preoperative exam, nine patients (42%) had one or more lesions, with infarct in four patients, white matter injury in four patients, and hemorrhage in five. We were unable to find any correlation between the data collected and brain injury. On postoperative exam, there was one new infarct, two new cases of white matter injury, and three cases of hemorrhage but no worsening of the preoperative lesions. Based on this initial experience with brain imaging, there is no deleterious effect of warm perfusion and no rationale to postpone surgery in neonates with "subclinical" brain injury. PMID:21995580

  16. Analysis of a simple square magnetic lattice for ultracold atoms

    NASA Astrophysics Data System (ADS)

    Ghanbari, Saeed; Abdalrahman, Ahmed; Sidorov, Andrei; Hannaford, Peter

    2014-06-01

    We investigate the conditions under which a proposed square magnetic lattice, produced by a periodic array of square holes patterned on a magnetic film plus bias fields, can lead to magnetic microtraps with non-zero potential minima suitable for trapping periodic arrays of ultracold atoms and quantum degenerate gases. We find that the magnetic field pattern created by the array of square holes plus bias fields exhibits a complex dependence on distance z from the magnetic film, due largely to competing contributions from kz and \\sqrt 2 kz decay terms (where k = 2π/a and a is the lattice period) and interference between the magnetic field pattern of the square-hole structure and the bias fields. We find that in order to avoid zero potential minima and hence losses due to Majorana spin flips, bias fields of unequal magnitude need to be applied along both the x and y (in-plane) directions plus a bias field within a specific range along the z (perpendicular) direction. We also find that for a finite-size (ns × ns) lattice, a z-bias field B1z ≈ -6\\sqrt 2M0(t/a)n_s^{-1} (where M0 and t are the film magnetization and thickness) is needed to compensate for the effect of the missing magnetic structure which would otherwise reduce the magnetic potential minima to zero.

  17. Spin nutation induced by atomic motion in a magnetic lattice

    SciTech Connect

    Kobayashi, Y.; Shiraishi, Y.; Hatakeyama, A.

    2010-12-15

    An atom moving in a spatially periodic field experiences a temporally periodic perturbation and undergoes a resonance transition between atomic internal states when the transition frequency is equal to the atomic velocity divided by the field period. We demonstrated that spin nutation was induced by this resonant transition in a polarized rubidium (Rb) atomic beam passing through a magnetic lattice. The lattice was produced by current flowing through an array of parallel wires crossing the beam. This array structure, reminiscent of a multiwire chamber for particle detection, allowed the Rb beam to pass through the lattice at a variety of incident angles. The dephasing of spin nutation was reduced by varying the incident angle.

  18. Effect of a primordial magnetic field on the inflaton decay process in a warm inflation scenario

    NASA Astrophysics Data System (ADS)

    Bastero-Gil, M.; Piccinelli, G.; Sanchez, A.

    2015-11-01

    Magnetic fields appear everywhere in the Universe. Their widespread presence at high redshifts and very large scales suggests that their origin could be primordial. In particular, their presence during the inflationary epoch can certainly not be ruled out. In the warm inflation scenario, the coupling of the inflaton to other bosonic and fermionic fields gives rise to dissipative effects that modify the inflationary dynamics. Since primordial magnetic fields could have an effect on both the effective inflationary potential and the inflaton decay process, their contribution must be considered together with the finite temperature corrections. We review here their effect on the inflationary potential and present preliminary results of their intervention in the dissipation process.

  19. Dynamics of neutral atoms in artificial magnetic field

    NASA Astrophysics Data System (ADS)

    Yu, Zi-Fa; Hu, Fang-Qi; Zhang, Ai-Xia; Xue, Ju-Kui

    2016-02-01

    Cyclotron dynamics of neutral atoms in a harmonic trap potential with artificial magnetic field is studied theoretically. The cyclotron orbit is obtained analytically and confirmed numerically. When the external harmonic potential is absent, artificial magnetic field can result in the singly periodic circular motion of Bose gas with the emergence of a Lorentz-like force, which is similar to particles with electric charge moving in a magnetic field. However, the coupling between artificial magnetic field and harmonic trap potential leads to rich and complex cyclotron trajectory, which depends on √{B2 + 1 }, where B is the rescaled artificial magnetic field. When √{B2 + 1 } is a rational number, the cyclotron orbit is multiply periodic and closed. However, when √{B2 + 1 } is an irrational number, the cyclotron orbit is quasiperiodic, i.e., the cyclotron motion of Bose gas is limited in a annular region, and eventually, the motion is ergodic in this region. Furthermore, the cyclotron orbits also depend on the initial conditions of Bose gas. Thus, the cyclotron dynamics of Bose gas can be manipulated in a controllable way by changing the artificial magnetic field, harmonic trap potential and initial conditions. Our results provide a direct theoretical evidence for the cyclotron dynamics of neutral atoms in the artificial gauge field.

  20. Effects of magnetic atoms on the properties of ternary superconductors

    SciTech Connect

    Dunlap, B.D.; Shenoy, G.K.

    1980-01-01

    Until recently it has been commonly accepted that small impurities of magnetic atoms were severely detrimental to superconductivity, and that superconductivity and long-range magnetic ordering could not occur in the same materials. In known binary and pseudo-binary compounds, this is still the case. However, many recent experiments on ternary superconductors have shown that the effects of magnetism are considerably more complex. In some cases, the addition of magnetic atoms has been found to enhance superconducting properties by increasing the superconducting critical field, without significantly lowering the transition temperature. In many cases, compounds will show both superconducting and long range magnetic ordering transitions. The destruction of superconductivity by ferromagnetic ordering and the coexistence of superconductivity with antiferromagnetic ordering is now well established. Hyperfine interaction measurements have played a significant role in the investigations of these materials, including measurement of the magnitude of the exchange interaction between rare-earth spin and conduction electron spin, elucidation of the mechanism for critical field enhancement, specification of crystalline field ground states, and studies of the nature of magnetic ordering.

  1. Pulse pumping high spatial resolution atomic magnetic microscopy

    NASA Astrophysics Data System (ADS)

    Hu, Xuyang; Huang, Haichao; Chen, Lin; Dong, Haifeng

    2015-05-01

    Atom vapor magnetometer is currently the most sensitive magnetometer with the fundamental sensitivity of 0 . 012 fT .cm-3 .Hz-1/2 and a measured sensitivity of 0 . 16 fT .Hz-1/2 with a measurement volume of 0 . 45cm3. However, the spatial resolution is limited to millimeter scale even with the buffer gas because of the atom diffusion. We present a way to limit atom diffusion range and improve the spatial resolution by using short pulse pumping and CCD detector. The diffusion model and spin-exchange relaxation time are used to calculate theoretically the relation between the spatial resolution and the magnetic sensitivity, which shows that sensitivity-resolution product of the atomic magnetic microscopy (MM) is smaller than that of other MMs, such as scanning SQUID MM, NV diamond MM and BEC MM. The pulse pumping is generated using Photodigm DBR 180TS laser which can output a short pulse light of 300 ns with a power of 180 mW. The magnetic image is obtained from the laser spot images received by a Manta G145 NIR CCD. This work was supported in part by the NSF of China (61074171, 61273067) and National Program on Key Basic Research Project of China (2012CB934104).

  2. Ultrasensitive magnetic field detection using a single artificial atom.

    PubMed

    Bal, M; Deng, C; Orgiazzi, J-L; Ong, F R; Lupascu, A

    2012-01-01

    Efficient detection of magnetic fields is central to many areas of research and technology. High-sensitivity detectors are commonly built using direct-current superconducting quantum interference devices or atomic systems. Here we use a single artificial atom to implement an ultrasensitive magnetometer with micron range size. The artificial atom, a superconducting two-level system, is operated similarly to atom and diamond nitrogen-vacancy centre-based magnetometers. The high sensitivity results from quantum coherence combined with strong coupling to magnetic field. We obtain a sensitivity of 3.3 pT Hz(-1/2) for a frequency at 10 MHz. We discuss feasible improvements to increase sensitivity by one order of magnitude. The intrinsic sensitivity of this detector at frequencies in the 100 kHz-10 MHz range compares favourably with direct-current superconducting quantum interference devices and atomic magnetometers of equivalent spatial resolution. This result illustrates the potential of artificial quantum systems for sensitive detection and related applications. PMID:23271657

  3. Atomically thin dilute magnetism in Co-doped phosphorene

    NASA Astrophysics Data System (ADS)

    Seixas, L.; Carvalho, A.; Castro Neto, A. H.

    2015-04-01

    Two-dimensional dilute magnetic semiconductors can provide fundamental insights into the very nature of magnetic order and their manipulation through electron and hole doping. Besides the fundamental interest, due to the possibility of control of charge density, they can be extremely important in spintronics applications such as spin valve and spin-based transistors. In this paper, we studied a two-dimensional dilute magnetic semiconductor consisting of a phosphorene monolayer doped with cobalt atoms in substitutional and interstitial defects. We show that these defects can be stabilized and are electrically active. Furthermore, by including holes or electrons by a potential gate, the exchange interaction and magnetic order can be engineered, and may even induce a ferromagnetic-to-antiferromagnetic phase transition in p -doped phosphorene. At a Co concentration of 2.7%, we estimate a Curie temperature of TCMF A=466 K in the mean-field approximation.

  4. Reinventing atomic magnetic simulations with spin-orbit coupling

    DOE PAGESBeta

    Perera, Meewanage Dilina N.; Eisenbach, Markus; Nicholson, Don M.; Stocks, George Malcolm; Landau, David P.

    2016-02-10

    We propose a powerful extension to the combined molecular and spin dynamics method that fully captures the coupling between the atomic and spin subsystems via spin-orbit interactions. Moreover, the foundation of this method lies in the inclusion of the local magnetic anisotropies that arise as a consequence of the lattice symmetry breaking due to phonons or crystallographic defects. By using canonical simulations of bcc iron with the system coupled to a phonon heat bath, we show that our extension enables the previously unachievable angular momentum exchange between the atomic and spin degrees of freedom.

  5. Electron Dynamics of Atoms in Parallel Electric and Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Yang, Hai-Feng; Gao, Wei; Cheng, Hong; Liu, Hong-Ping

    2014-10-01

    Through an analysis of the nearest neighbor level spacing statistics for atoms in parallel electric and magnetic fields, we investigate the evolution of the electron dynamics as electric field strength increases. In the ‘inter-l mixing’ predominant region, the electron shows complex dynamics while in the ‘inter-n mixing’ predominant region, its dynamics behaves in a relatively stable way and the characteristic quantity ξ shows a slight oscillation. Comparing the dynamics for hydrogen and barium, we find that the core effect makes the main contribution to the chaotic behavior in non-hydrogen atoms.

  6. Environmental magnetic evidence for a dynamic Taylor Glacier during the mid-Pliocene warm period

    NASA Astrophysics Data System (ADS)

    Ohneiser, Christian; Wilson, Gary; Florindo, Fabio

    2010-05-01

    The current understanding of the Neogene history of the East Antarctic Ice Sheet (EAIS) is limited spatially and temporally by a paucity of sedimentary records. This has led to the assumption that the Antarctic Glacio-climatic system has been in stasis since middle Miocene times and such an interpretation is not in conflict with deep-sea stable isotope records. However, rare stratified glacigene deposits exposed in the Transantarctic mountains and recovered from beneath Antarctic fjords by drilling suggest a more dynamic history of the EAIS. We apply environmental magnetic methods to drill cores previously collected from McMurdo Sound in an effort to track processes, transport methods and conditions and environments of deposition through the late Neogene. Additionally, we assess the robustness of the earlier magnetostratigraphies from the DVDP-10 and -11 cores by undertaking the first comprehensive paleomagnetic study of discrete paleomagnetic samples with complete thermal and alternating field demagnetisation and polarity determinations from principal component analysis. Here we present results from an investigation of the magnetic properties of the DVDP-10 and DVDP-11 drill cores from New Harbour, southern Victoria Land. Magnetic properties were determined for 400 samples by measuring their magnetic susceptibility, thermomagnetism and natural and anhysteretic remanent magnetism (NRM/ARM) at the Otago Paleomagnetic Research Facility and hysteresis and isothermal remanent magnetism (IRM) at the Istituto Nazionale di Geofisica e Vulcanologia in Rome, Italy. The initial analyses indicate that only minimal diagenetic alteration has occurred and that a primary environmental magnetic signal is intact. We divide these records into three intervals based on magnetic characteristics. The upper interval (Interval I) comprises latest Pliocene to Pleistocene age Ross Sea Ice derived sediments which have high concentrations of fine grained magnetite reflecting the contribution of McMurdo Volcanic material to the signal. At ~200 meters in DVDP-11 and ~155 m in DVDP-10 a major mid-Pliocene hiatus truncates a ~40 meter thick interval (Interval II) of muds and diamicts which represents the mid-Pliocene warm period. Magnetically, this interval is unique within the cores because it has relatively low concentrations of magnetite and an upward fining of the magnetic grainsize. We suggest that this interval represents a retreated Taylor Glacier system under warm conditions followed by a re-advance under cooler conditions. The glacial advance immediately prior to the unconformity is marked by increasing magnetite concentration in parallel with decreasing magnetic grain size. The unconformity itself marks a switch from Taylor Valley or EAIS-derived sediments below to Ross Sea Ice or WAIS-derived sediments above. Below Interval II and to the base of each core are mid-Pliocene to latest Miocene Taylor Valley derived diamicts. Magnetic grainsizes and concentrations are variable over this interval indicating a dynamic Taylor Glacier which underwent multiple advances and retreats. Efforts are underway to correlate the magnetic properties of these cores with comparable interval in the ANDRILL MIS and SMS cores in order to build a more comprehensive regional understanding of this period.

  7. Soft magnetic composites manufactured by warm co-extrusion of bulk metallic glass and steel powders

    SciTech Connect

    Johnson, Francis; Raber, Thomas R.; Zabala, Robert J.; Buresh, Steve J.; Tanico, Brian

    2013-05-07

    Soft magnetic composites of Fe-based bulk metallic glass and low-alloy steel have been manufactured by warm co-extrusion of precursor powders at temperatures within the supercooled liquid region of the glass. Composites were manufactured with amorphous volume fractions of 75%, 67%, and 100%. Full consolidation of the constituent powders was observed with the bulk metallic glass remaining substantially amorphous. The composite electrical resistivity was observed to be anisotropic with a resistivity of 79 {mu}{Omega} cm measured transverse to the extrusion axis in a sample with 75% amorphous volume fraction. A 0-3 connectivity pattern with the low-resistivity steel phase embedded in a 3-dimensionally connected high-resistivity bulk metallic glass phase was observed with scanning electron microscopy. This confirms that the flow characteristics of the bulk metallic glass and the steel powders were comparable during extrusion at these temperatures. The saturation magnetization of 1.3 T was consistent with the volume weighted average of the saturation magnetization of the two phases. A relatively high quasistatic coercivity of 8 Oe was measured and is likely due to slight crystallization of the bulk metallic glass as well as domain wall pinning at prior particle boundaries. Careful control of the thermal environment during the extrusion process is required to minimize glass crystallization and achieve the desired balance of magnetic and electrical properties.

  8. Simple basis for hydrogenic atoms in magnetic fields

    SciTech Connect

    Gallas, J.A.C.

    1984-01-01

    A field-dependent hydrogenic basis is used to obtain the evolution of the energy spectrum of atoms in strong (approx.10/sup 8/ G) and uniform magnetic fields. The basis allows results to be derived analytically. Numerical values for the first 13 excited states of hydrogen are found to be in very good agreement with much more elaborate calculations of Smith et al. and of Brandi. In addition, the possibility of having a remnant type of degeneracy in the presence of the magnetic field is investigated.

  9. Guiding and Trapping of Rydberg atoms in a linear magnetic atom guide

    NASA Astrophysics Data System (ADS)

    Hempel, Cornelius; Traxler, Mallory; Vaidya, Varun; Raithel, Georg

    2009-05-01

    We describe an experimental approach and present results on the dynamics of Rydberg atoms in a high-gradient magnetic guiding and trapping apparatus. The setup consists of two parallel current-carrying wires providing a quadrupole trapping potential with a gradient of 2.7 kG.cm-1 at its center. A Ioffe-Pritchard type trap can be formed by superposition of an inhomogeneous longitudinal bias field. Rubidium Rydberg atoms are excited using the two-photon transition 5S1/2 -> 5P3/2 -> nL, where n and L are principal and angular-momentum quantum numbers. An ion-imaging insert allows for time-delayed and spatially resolved detection of the excited atoms and their motion within the trapping potential. The excitation geometry is suitable for coherent, highly efficient population of circular Rydberg levels using adiabatic transfer in crossed magnetic and time-dependent electric fields. Circular-state atoms have long radiative lifetimes and small electric polarizabilities, making them ideal for Rydberg-atom trapping experiments and for studies that require long coherence times.

  10. Designing Frustrated Quantum Magnets with Laser-Dressed Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Glaetzle, Alexander W.; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

    2015-05-01

    We show how a broad class of lattice spin-1 /2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1 /2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments.

  11. Designing frustrated quantum magnets with laser-dressed Rydberg atoms.

    PubMed

    Glaetzle, Alexander W; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

    2015-05-01

    We show how a broad class of lattice spin-1/2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1/2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments. PMID:25978228

  12. Imaging of brain magnetic fields with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Ben-Amar Baranga, A.; Hoffman, D. E.; Romalis, M. V.

    2004-05-01

    Measurements of the magnetic fields generated by the brain (Magnetoencephalography or MEG) are widely used for non-invasive studies of the brain. They typically use arrays of hundreds of SQUID detectors operating in liquid Helium. We are developing a new multi-channel atomic magnetometer suitable for mapping of magnetic fields from a human brain. The magnetometer uses high-density K vapor and operates in a very low magnetic field, eliminating the broadening due to spin-exchange collisions. We have previously demonstrated a 7-channel magnetometer with magnetic field sensitivity exceeding the sensitivity of SQUID detectors [1]. Currently we are constructing a 256-channel magnetometer system operating in a human-size magnetic shield. The magnetic fields will be measured on a two-dimensional grid in a cubical cell approximately 7 cm on the side located about 2 cm away from a human head. Numerical simulations indicate that spatial localization of the magnetic field sources within the brain should be improved by more than one order of magnitude compared with traditional SQUID systems. [1] I. K. Kominis, T. W. Kornack, J. C. Allred and M. V. Romalis, Nature, 422, 596 (2003).

  13. Atomic magnetic gradiometer for room temperature high sensitivity magnetic field detection

    DOEpatents

    Xu,Shoujun; Lowery, Thomas L.; Budker, Dmitry; Yashchuk, Valeriy V.; Wemmer, David E.; Pines, Alexander

    2009-08-11

    A laser-based atomic magnetometer (LBAM) apparatus measures magnetic fields, comprising: a plurality of polarization detector cells to detect magnetic fields; a laser source optically coupled to the polarization detector cells; and a signal detector that measures the laser source after being coupled to the polarization detector cells, which may be alkali cells. A single polarization cell may be used for nuclear magnetic resonance (NMR) by prepolarizing the nuclear spins of an analyte, encoding spectroscopic and/or spatial information, and detecting NMR signals from the analyte with a laser-based atomic magnetometer to form NMR spectra and/or magnetic resonance images (MRI). There is no need of a magnetic field or cryogenics in the detection step, as it is detected through the LBAM.

  14. Understanding atomic disorder in polar and magnetic oxides

    NASA Astrophysics Data System (ADS)

    Shoemaker, Daniel P.

    The functional properties of materials rely upon the composition, coordination, and connectivity of their constituent atoms. Understanding the atomic structure of condensed materials permits an understanding of how that structure influences macroscopic properties. The field of crystallography seeks to define the repeating lattice of periodic materials using a unit cell model with the minimum number of specified atomic positions. For magnetic and electronic materials, the arrangement of atoms and dipoles are often both ordered over long ranges and amenable to a traditional crystallographic description. However, interesting phenomena emerge when materials experience disorder due to chemical substitution, phase competition, nanostructuring, interfaces, or valence disproportionation. In those cases, the long-range symmetry of the material is interrupted and traditional crystallographic methods struggle to incorporate disorder into the unit cell model. I will discuss how disorder can be identified and quantified in functional materials. Each study includes examination of the real-space pair distribution function (PDF), which provides a weighted histogram of all atom-atom distances in a sample. Models are created by simultaneous fits to the Bragg profile and the PDF, thereby constraining the atomic positions by reciprocal- and real-space scattering descriptions. The reverse Monte Carlo method drives stochastic fits to scattering data using tens of thousands of atoms. Once simulation is complete, crystallographic metrics can be extracted from the supercell in real space. This approach is discussed in the case of site mixing and valence disproportionation in the Jahn-Teller active spinel CuMn2O4, local Jahn-Teller distortions of CuO4 tetrahedra in the solid solution Mg 1-xCuxCr 2O4, nanoscale phase co-existence at the metal-insulator transition in VO2, and static displacements and lone-pair activity in the pyrochlores Bi2Ti2O6O' and Bi 2Ru2O6O'.

  15. Atom interferometry in space: Thermal management and magnetic shielding

    SciTech Connect

    Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

    2014-08-15

    Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10{sup −4} % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 10{sup 5}. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

  16. Atom interferometry in space: thermal management and magnetic shielding.

    PubMed

    Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman; Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

    2014-08-01

    Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10(-4) % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 10(5). We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space. PMID:25173244

  17. Atom interferometry in space: Thermal management and magnetic shielding

    NASA Astrophysics Data System (ADS)

    Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman; Rievers, Benny; Herrmann, Sven; Schuldt, Thilo; Braxmaier, Claus

    2014-08-01

    Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10-4 % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 105. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

  18. Charge distribution of a strongly magnetized Thomas-Fermi atom

    SciTech Connect

    Lief, E.; Weisheit, J.

    1993-05-01

    Thomas-Fermi theory provides a model for multielectron atoms in ultrastrong magnetic fields, B > 10{sup 12} Gauss, but the resulting equation has only been solved under the restrictive assumption of spherical symmetry. We have extended this model by: (1) recasting it in terms of an explicit equation for the charge density n; and (2), solving the resulting equation in cylindrical coordinates, with an axially symmetric factorization ansatz, n = ng(g)n{sub z} (g, z). The radial factor ng(g) we obtained from Landau wavefunctions which, in contrast to some previous pictures by others, yield an almost uniform function of radius with a sharp fall at the atom`s edge. The equation for the other charge density factor, n{sub z} (g, z), is a nonlinear second order equation in partial derivatives, which does not have analytical solutions in its general form. However, we have solved it analytically under different approximations. Our strongly magnetized atom has, as expected, an elongated form, with longitudinal and transverse dimensions being contracted roughly in proportion to {radical}2/B, and it shows features consistent both with other qualitative treatments and with published numerical results for hydrogen. A finite difference method is being adopted for numerical solution of the general equation. Due to a specific normalization condition, which we substitute for one boundary condition, this method evidently is better than a finite element approach.

  19. Optical atomic magnetometer at body temperature for magnetic particle imaging and nuclear magnetic resonance.

    PubMed

    Garcia, Nissa C; Yu, Dindi; Yao, Li; Xu, Shoujun

    2010-03-01

    Optical atomic magnetometers are often bulky and operate at elevated temperatures that impose restrictions on studying biological samples. Here we report a miniaturized Cs-based magnetometer, in contrast to conventionally used K- and Rb-based ones, with high sensitivity. The magnetic shield employed is more compact, and the optimal operation temperature of 37 degrees C is lower than previous magnetometers and is suitable for biological research. Applications include scanning magnetic imaging of functionalized magnetic particles and nuclear magnetic resonance of water. We reveal that the stability and sensitivity of the apparatus are not significantly affected by the absence of a laser stabilization device. PMID:20195311

  20. Atomic spin chains as testing ground for quantum magnetism

    NASA Astrophysics Data System (ADS)

    Otte, Sander

    2015-03-01

    The field of quantum magnetism aims to capture the rich emergent physics that arises when multiple spins interact, in terms of elementary models such as the spin 1/2 Heisenberg chain. Experimental platforms to verify these models are rare and generally do not provide the possibility to detect spin correlations locally. In my lab we use low-temperature scanning tunneling microscopy to design and build artificial spin lattices with atomic precision. Inelastic electron tunneling spectroscopy enables us to identify the ground state and probe spin excitations as a function of system size, location inside the lattice and coupling parameter values. Two types of collective excitations that play a role in many dynamic magnetic processes are spin waves (magnons) and spinons. Our experiments enable us to study both types of excitations. First, we have been able to map the standing spin wave modes of a ferromagnetic bit of six atoms, and to determine their role in the collective reversal process of the bit (Spinelli et al., Nature Materials 2014). More recently, we have crafted antiferromagnetic spin 1/2 XXZ chains, which allow us to observe spinon excitations, as well as the stepwise transition to a fully aligned phase beyond the critical magnetic field (Toskovic et al., in preparation). These findings create a promising experimental environment for putting quantum magnetic models to the test. Research funded by NWO and FOM.

  1. Simulating and detecting artificial magnetic fields in trapped atoms

    SciTech Connect

    Rosenkranz, Matthias; Klein, Alexander; Jaksch, Dieter

    2010-01-15

    A Bose-Einstein condensate exhibiting a nontrivial phase induces an artificial magnetic field in immersed impurity atoms trapped in a stationary, ring-shaped optical lattice. We present an effective Hamiltonian for the impurities for two condensate setups: the condensate in a rotating ring and in an excited rotational state in a stationary ring. We use Bogoliubov theory to derive analytical formulas for the induced artificial magnetic field and the hopping amplitude in the limit of low condensate temperature where the impurity dynamics is coherent. As methods for observing the artificial magnetic field we discuss time-of-flight imaging and mass current measurements. Moreover, we compare the analytical results of the effective model to numerical results of a corresponding two-species Bose-Hubbard model. We also study numerically the clustering properties of the impurities and the quantum chaotic behavior of the two-species Bose-Hubbard model.

  2. Thermometry of Red Blood Cell Concentrate: Magnetic Resonance Decoding Warm Up Process

    PubMed Central

    Wagner, Thomas; Kozma, Noemi; Roland, Jörg; Schöllnast, Helmut; Ebner, Franz; Lanzer, Gerhard

    2013-01-01

    Purpose Temperature is a key measure in human red blood cell concentrate (RBC) quality control. A precise description of transient temperature distributions in RBC units removed from steady storage exposed to ambient temperature is at present unknown. Magnetic resonance thermometry was employed to visualize and analyse RBC warm up processes, to describe time courses of RBC mean, surface and core temperatures by an analytical model, and to determine and investigate corresponding model parameters. Methods Warm-up processes of 47 RBC units stored at 1–6°C and exposed to 21.25°C ambient temperature were investigated by proton resonance frequency thermometry. Temperature distributions were visualized and analysed with dedicated software allowing derivation of RBC mean, surface and core temperature-time courses during warm up. Time-dependence of mean temperature was assumed to fulfil a lumped capacitive model of heat transfer. Time courses of relative surface and core temperature changes to ambient temperature were similarly assumed to follow shifted exponential decays characterized by a time constant and a relative time shift, respectively. Results The lumped capacitive model of heat transfer and shifted exponential decays described time-dependence of mean, surface and core temperatures close to perfect (mean R2 were 0.999±0.001, 0.996±0.004 and 0.998±0.002, respectively). Mean time constants were τmean = 55.3±3.7 min, τsurface = 41.4±2.9 min and τcore = 76.8±7.1 min, mean relative time shifts were Δsurface = 0.07±0.02 and Δcore = 0.04±0.01. None of the constants correlated significantly with temperature differences between ambient and storage temperature. Conclusion Lumped capacitive model of heat transfer and shifted exponential decays represent simple analytical formulas to describe transient mean, surface and core temperatures of RBC during warm up, which might be a helpful tool in RBC temperature monitoring and quality control. Independence of constants on differences between ambient and storage temperature suggests validity of models for arbitrary storage and ambient temperatures. PMID:23469108

  3. Photon statistics and polarization correlations at telecommunications wavelengths from a warm atomic ensemble.

    PubMed

    Willis, R T; Becerra, F E; Orozco, L A; Rolston, S L

    2011-07-18

    We present measurements of the polarization correlation and photon statistics of photon pairs that emerge from a laser-pumped warm rubidium vapor cell. The photon pairs occur at 780 nm and 1367 nm and are polarization entangled. We measure the autocorrelation of each of the generated fields as well as the cross-correlation function, and observe a strong violation of the two-beam Cauchy-Schwartz inequality. We evaluate the performance of the system as source of heralded single photons at a telecommunication wavelength. We measure the heralded autocorrelation and see that coincidences are suppressed by a factor of ≈ 20 from a Poissonian source at a generation rate of 1500 s(-1), a heralding efficiency of 10%, and a narrow spectral width. PMID:21934825

  4. Transport in ultrathin gold films decorated with magnetic Gd atoms

    NASA Astrophysics Data System (ADS)

    Alemani, Micol; Helgren, Erik; Hugel, Addison; Hellman, Frances

    2008-03-01

    We have performed four-probe transport measurements of ultrathin Au films decorated with Gd ad-atoms. The samples were prepared by quench condensation, i.e., sequential evaporation on a cryogenically cooled substrate under UHV conditions while monitoring the film thickness and resistance. Electrically continuous Au films at thickness of about 2 mono-layers of material are grown on an amorphous Ge wetting layer. The quench condensation method provides a sensitive control on the sample growth process, allowing us to tune the morphological and electrical configuration of the system. The ultrathin gold films develop from an insulating to a metallic state as a function of film thickness. The temperature dependence of the Au conductivity for different thickness is studied. It evolves from hopping transport for the insulating films, to a ln T dependence for thicker films. For gold films in the insulating regime we found a decreasing resistance by adding Gd. This is in agreement with a decreasing tunneling barrier height between metallic atoms. The Gd magnetic moments are randomly oriented for isolated atoms. This magnetic disorder leads to scattering of the charge carriers and a reduced conductivity compared to nonmagnetic materials.

  5. Cold magnetically trapped 2Dg scandium atoms. II. Scattering dynamics

    NASA Astrophysics Data System (ADS)

    Karman, Tijs; Groenenboom, Gerrit C.

    2014-11-01

    The binary collision dynamics of 2Dg ,3 /2 ground state scandium atoms is studied from first principles. We employ 30 coupled diabatic ab initio potentials in a coupled-channels study of the scattering dynamics of cold and ultracold scandium atoms in external magnetic fields. Due to the long-ranged magnetic dipolar interaction, the field dependence of the cross section does not follow the threshold laws derived by Volpi and Bohn [Phys. Rev. A 65, 052712 (2002), 10.1103/PhysRevA.65.052712]. In the field-free case, the near-threshold cross section is independent of the collision energy, and hence the cross section does not follow the well-established Wigner threshold laws. The observed threshold behavior is explained in the Born approximation. For energies above 1 ? K , inelastic collisions are driven by the anisotropic nonrelativistic electronic interaction. For energies below 100 ? K , the ratio of elastic-to-inelastic collisions is likely to be favorable for evaporative cooling. Both anisotropy in the long-range interaction and in the short-range potential contribute to large cross sections for inelastic collisions at higher energies and lead to a small ratio of elastic-to-inelastic collisions. This is in agreement with the large rates for Zeeman relaxation of submerged-shell atoms observed experimentally. The effect of the uncertainty in the ab initio potential is sampled by scaling the reduced mass and is found to have little influence on the conclusions drawn from this work.

  6. Nonlocal electron transport in magnetized plasmas with arbitrary atomic number

    SciTech Connect

    Bennaceur-Doumaz, D.; Bendib, A.

    2006-09-15

    The numerical solution of the steady-state electron Fokker-Planck equation perturbed with respect to a global equilibrium is presented in magnetized plasmas with arbitrary atomic number Z. The magnetic field is assumed to be constant and the electron-electron collisions are described by the Landau collision operator. The solution is derived in the Fourier space and in the framework of the diffusive approximation which captures the spatial nonlocal effects. The transport coefficients are deduced and used to close a complete set of nonlocal electron fluid equations. This work improves the results of A. Bendib et al. [Phys. Plasmas 9, 1555 (2002)] and of A. V. Brantov et al. [Phys. Plasmas 10, 4633 (2003)] restricted to the local and nonlocal high-Z plasma approximations, respectively. The influence of the magnetic field on the nonlocal effects is discussed. We propose also accurate numerical fits of the relevant transport coefficients with respect to the collisionality parameter {lambda}{sub ei}/L and the atomic number Z, where L is the typical scale length and {lambda}{sub ei} is the electron-ion mean-free-path.

  7. Nanoscale magnetic resonance imaging and magnetic sensing using atomic defects in diamond

    NASA Astrophysics Data System (ADS)

    Grinolds, Michael

    Magnetic resonance imaging (MRI) has revolutionized modern medicine by providing non-invasive, chemically selective, three-dimensional imaging of living organisms. Industrial-scale MRI has the capability to image with millimeter-scale spatial resolution and has the sensitivity to detect as few as 1014 nuclear spins. Increasing spatial resolution to the atomic scale and sensitivity to the single-spin level would enable a wide array of applications most notably including imaging molecular structur. However, conventional MRI methods are already highly optimized, and further order-of-magnitude-scale improvements cannot be reasonably expected without employing fundamentally different technologies. This thesis presents an alternative approach to conventional MRI that pushes resolution and sensitivity to the individual atom and molecular level. The guiding principle for achieving multiple order-of-magnitude improvements is to miniaturize the key components of MRI: the detector and the source of magnetic-field gradients. By scaling down the physical size of these components to the nano- and atomic- scales, the signals from individual spins become measurable and resolvable. To miniature the detector, we employ an optically-active, paramagnetic atomic defect in diamond---a nitrogen-vacancy (NV) center---as our sensor. Owing to its optical readout, long coherence times, atomic-size, and room-temperature compatibility, NV centers in diamond have the capability to measure the magnetic fields from individual spins, provided the sensor can be placed sufficiently close to a target to be measured. This thesis describes the experimental realization of a microscope that can perform sensitive magnetometry experiments using a single NV center that magnetically images by spatially scanning the NV center within a few nanometers of magnetic targets. With this technique we are able to demonstrate the first room-temperature magnetic imaging of individual electron spins. For miniaturizing the magnetic-field gradient source, we use scanning nanoscale magnets, building off the success of those used in magnetic resonance force microscopy. By shrinking the magnetic field source to tens of nanometers in size, the magnitude of the magnetic field gradients can be increased by more than a factor of 105 compared to conventional MRI field gradients coils, which increases spatial resolution correspondingly. With these tips optimized for compatibility with NV-based measurements, we are able to achieve sub-nanometer resolution in MRI imaging.

  8. Spin-polarized currents generated by magnetic Fe atomic chains.

    PubMed

    Lin, Zheng-Zhe; Chen, Xi

    2014-06-13

    Fe-based devices are widely used in spintronics because of high spin-polarization and magnetism. In this work, freestanding Fe atomic chains, the thinnest wires, were used to generate spin-polarized currents due to the spin-polarized energy bands. By ab initio calculations, the zigzag structure was found to be more stable than the wide-angle zigzag structure and had a higher ratio of spin-up and spin-down currents. By our theoretical prediction, Fe atomic chains have a sufficiently long thermal lifetime only at T ≦̸ 150 K, while C atomic chains are very stable even at T = 1000 K. This means that the spintronic devices based on Fe chains could work only at low temperatures. A system constructed by a short Fe chain sandwiched between two graphene electrodes could be used as a spin-polarized current generator, while a C chain could not be used in this way. The present work may be instructive and meaningful to further practical applications based on recent technical developments on the preparation of metal atomic chains (Proc. Natl. Acad. Sci. USA 107 9055 (2010)). PMID:24849670

  9. First principles calculation of the structural, electronic, and magnetic properties of Au-Pd atomic chains

    SciTech Connect

    Dave, Mudra R.; Sharma, A. C.

    2015-06-24

    The structural, electronic and magnetic properties of free standing Au-Pd bimetallic atomic chain is studied using ab-initio method. It is found that electronic and magnetic properties of chains depend on position of atoms and number of atoms. Spin polarization factor for different atomic configuration of atomic chain is calculated predicting a half metallic behavior. It suggests a total spin polarised transport in these chains.

  10. Extended Bose-Hubbard models with ultracold magnetic atoms.

    PubMed

    Baier, S; Mark, M J; Petter, D; Aikawa, K; Chomaz, L; Cai, Z; Baranov, M; Zoller, P; Ferlaino, F

    2016-04-01

    The Hubbard model underlies our understanding of strongly correlated materials. Whereas its standard form only comprises interactions between particles at the same lattice site, extending it to encompass long-range interactions is predicted to profoundly alter the quantum behavior of the system. We realize the extended Bose-Hubbard model for an ultracold gas of strongly magnetic erbium atoms in a three-dimensional optical lattice. Controlling the orientation of the atomic dipoles, we reveal the anisotropic character of the onsite interaction and hopping dynamics and their influence on the superfluid-to-Mott insulator quantum phase transition. Moreover, we observe nearest-neighbor interactions, a genuine consequence of the long-range nature of dipolar interactions. Our results lay the groundwork for future studies of exotic many-body quantum phases. PMID:27124454

  11. Extended Bose-Hubbard models with ultracold magnetic atoms

    NASA Astrophysics Data System (ADS)

    Baier, S.; Mark, M. J.; Petter, D.; Aikawa, K.; Chomaz, L.; Cai, Z.; Baranov, M.; Zoller, P.; Ferlaino, F.

    2016-04-01

    The Hubbard model underlies our understanding of strongly correlated materials. Whereas its standard form only comprises interactions between particles at the same lattice site, extending it to encompass long-range interactions is predicted to profoundly alter the quantum behavior of the system. We realize the extended Bose-Hubbard model for an ultracold gas of strongly magnetic erbium atoms in a three-dimensional optical lattice. Controlling the orientation of the atomic dipoles, we reveal the anisotropic character of the onsite interaction and hopping dynamics and their influence on the superfluid-to-Mott insulator quantum phase transition. Moreover, we observe nearest-neighbor interactions, a genuine consequence of the long-range nature of dipolar interactions. Our results lay the groundwork for future studies of exotic many-body quantum phases.

  12. Microfabricated atomic vapor cell arrays for magnetic field measurements

    SciTech Connect

    Woetzel, S.; Schultze, V.; IJsselsteijn, R.; Schulz, T.; Anders, S.; Stolz, R.; Meyer, H.-G.

    2011-03-15

    We describe a method for charging atomic vapor cells with cesium and buffer gas. By this, it is possible to adjust the buffer gas pressure in the cells with good accuracy. Furthermore, we present a new design of microfabricated vapor cell arrays, which combine silicon wafer based microfabrication and ultrasonic machining to achieve the arrays of thermally separated cells with 50 mm{sup 3} volume. With cells fabricated in the outlined way, intrinsic magnetic field sensitivities down to 300 fT/Hz{sup 1/2} are reached.

  13. Magnetic blackbody shift of hyperfine transitions for atomic clocks

    SciTech Connect

    Berengut, J. C.; Flambaum, V. V.; King-Lacroix, J.

    2009-12-15

    We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T{sup 2} dependence only in the high-temperature limit. We also calculate the shift of ground-state p{sub 1/2} hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p{sub 3/2} fine-structure multiplet may be the dominant effect.

  14. Tracing Magnetic Fields by Atomic Alignment in Extended Radiation Fields

    NASA Astrophysics Data System (ADS)

    Zhang, Heshou; Yan, Huirong; Dong, Le

    2015-05-01

    Tracing magnetic field is crucial as magnetic field plays an important role in many astrophysical processes. Earlier studies have demonstrated that ground state alignment (GSA) is an effective way to detect a weak magnetic field (1G≳ B≳ {{10}-15} G) in a diffuse medium. We explore the atomic alignment in the presence of an extended radiation field for both absorption lines and emission lines. The alignment in the circumstellar medium, binary systems, disks, and the local interstellar medium are considered in order to study the alignment in the radiation field where the pumping source has a clear geometric structure. Furthermore, the multipole expansion method is adopted to study GSA induced in the radiation field with unidentified pumping sources. We study the alignment in the dominant radiation components of the general radiation field: the dipole and quadrupole radiation field. We discuss the approximation of GSA in a general radiation field by summing the contribution from the dipole and quadrupole radiation field. We conclude that GSA is a powerful tool for detecting weak magnetic fields in the diffuse medium in general radiation fields.

  15. Magnetic induction measurements using an all-optical {sup 87}Rb atomic magnetometer

    SciTech Connect

    Wickenbrock, Arne; Tricot, François; Renzoni, Ferruccio

    2013-12-09

    In this work we propose, and experimentally demonstrate, the use of a self-oscillating all-optical atomic magnetometer for magnetic induction measurements. Given the potential for miniaturization of atomic magnetometers, and their extreme sensitivity, the present work shows that atomic magnetometers may play a key role in the development of instrumentation for magnetic induction tomography.

  16. Collisional/resonance absorption in cold/warm magnetized plasmas of the F-region high-latitude ionosphere

    NASA Astrophysics Data System (ADS)

    Gondarenko, N. A.; Ossakow, S. L.; Bernhardt, P. A.

    2009-05-01

    The collisional/resonance absorption due to linear mode conversion of electromagnetic waves into electrostatic/plasma waves is studied in cold/warm magnetized plasmas relevant to the F-region of the high-latitude ionosphere. The absorption coefficient is calculated numerically using a full-wave model for high-frequency waves incident normally/obliquely to the direction of inhomogeneity. The absorption coefficient of collisional cold plasmas is found to be independent of the collision frequency in the small range of incidence angles near the critical angle; whereas, outside this range absorption increases with increasing collisions. In warm collisionless plasmas, the resonance absorption coefficient is shown to be independent of the electron temperature values pertinent to the F-region plasma. We have demonstrated for the first time a strong effect of the external magnetic field arbitrarily oriented in the plane of incidence on the absorption coefficient, which is not pronounced in the limit of weakly magnetized plasmas.

  17. Artificial Staggered Magnetic Field for Ultracold Atoms in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Morais Smith, Cristiane

    2011-03-01

    Uniform magnetic fields are ubiquitous in nature, but this is not the case for staggered magnetic fields. In this talk, I will discuss an experimental set-up for cold atoms recently proposed by us, which allows for the realization of a ``staggered gauge field'' in a 2D square optical lattice. If the lattice is loaded with bosons, it may be described by an effective Bose-Hubbard Hamiltonian, with complex and anisotropic hopping coefficients. A very rich phase diagram emerges: besides the usual Mott-insulator and zero-momentum condensate, a new phase with a finite momentum condensate becomes the ground-state at strong gauge fields. By using the technique of Feshbach resonance, the dynamics of a coherent superposition of a vortex-carrying atomic condensate and a conventional zero-momentum molecular condensate can also be studied within the same scheme. On the other hand, if the lattice is loaded with fermions, a highly tunable, graphene-like band structure can be realized, without requiring the honeycomb lattice symmetry. When the system is loaded with a mixture of bosons and two-species fermions, several features of the high-Tc phase diagram can be reproduced. A dome-shaped unconventional superconducting region arises, surrounded by a non-Fermi liquid and a Fermi liquid at low and high doping, respectively. We acknowledge financial support from the Netherlands Organization for Scientific Research (NWO).

  18. Cold and warm atomic gas around the Perseus molecular cloud. I. Basic properties

    SciTech Connect

    Stanimirović, Snežana; Murray, Claire E.; Miller, Jesse; Lee, Min-Young

    2014-10-01

    Using the Arecibo Observatory, we have obtained neutral hydrogen (HI) absorption and emission spectral pairs in the direction of 26 background radio continuum sources in the vicinity of the Perseus molecular cloud. Strong absorption lines were detected in all cases, allowing us to estimate spin temperature (T{sub s} ) and optical depth for 107 individual Gaussian components along these lines of sight. Basic properties of individual H I clouds (spin temperature, optical depth, and the column density of the cold and warm neutral medium (CNM and WNM), respectively) in and around Perseus are very similar to those found for random interstellar lines of sight sampled by the Millennium H I survey. This suggests that the neutral gas found in and around molecular clouds is not atypical. However, lines of sight in the vicinity of Perseus have, on average, a higher total H I column density and the CNM fraction, suggesting an enhanced amount of cold H I relative to an average interstellar field. Our estimated optical depth and spin temperature are in stark contrast with the recent attempt at using Planck data to estimate properties of the optically thick H I. Only ∼15% of lines of sight in our study have a column density weighted average spin temperature lower than 50 K, in comparison with ≳ 85% of Planck's sky coverage. The observed CNM fraction is inversely proportional to the optical depth weighted average spin temperature, in excellent agreement with the recent numerical simulations by Kim et al. While the CNM fraction is, on average, higher around Perseus relative to a random interstellar field, it is generally low, between 10%-50%. This suggests that extended WNM envelopes around molecular clouds and/or significant mixing of CNM and WNM throughout molecular clouds are present and should be considered in the models of molecule and star formation. Our detailed comparison of H I absorption with CO emission spectra shows that only 3 of the 26 directions are clear candidates for probing the CO-dark gas as they have N(H I)>10{sup 21} cm{sup –2} yet no detectable CO emission.

  19. Cold and Warm Atomic Gas around the Perseus Molecular Cloud. I. Basic Properties

    NASA Astrophysics Data System (ADS)

    Stanimirović, Snežana; Murray, Claire E.; Lee, Min-Young; Heiles, Carl; Miller, Jesse

    2014-10-01

    Using the Arecibo Observatory, we have obtained neutral hydrogen (HI) absorption and emission spectral pairs in the direction of 26 background radio continuum sources in the vicinity of the Perseus molecular cloud. Strong absorption lines were detected in all cases, allowing us to estimate spin temperature (Ts ) and optical depth for 107 individual Gaussian components along these lines of sight. Basic properties of individual H I clouds (spin temperature, optical depth, and the column density of the cold and warm neutral medium (CNM and WNM), respectively) in and around Perseus are very similar to those found for random interstellar lines of sight sampled by the Millennium H I survey. This suggests that the neutral gas found in and around molecular clouds is not atypical. However, lines of sight in the vicinity of Perseus have, on average, a higher total H I column density and the CNM fraction, suggesting an enhanced amount of cold H I relative to an average interstellar field. Our estimated optical depth and spin temperature are in stark contrast with the recent attempt at using Planck data to estimate properties of the optically thick H I. Only ~15% of lines of sight in our study have a column density weighted average spin temperature lower than 50 K, in comparison with >~ 85% of Planck's sky coverage. The observed CNM fraction is inversely proportional to the optical depth weighted average spin temperature, in excellent agreement with the recent numerical simulations by Kim et al. While the CNM fraction is, on average, higher around Perseus relative to a random interstellar field, it is generally low, between 10%-50%. This suggests that extended WNM envelopes around molecular clouds and/or significant mixing of CNM and WNM throughout molecular clouds are present and should be considered in the models of molecule and star formation. Our detailed comparison of H I absorption with CO emission spectra shows that only 3 of the 26 directions are clear candidates for probing the CO-dark gas as they have N(H I)>1021 cm-2 yet no detectable CO emission.

  20. Magnetic nanodots from atomic Fe: Can it be done?

    PubMed Central

    te Sligte, E.; Bosch, R. C. M.; Smeets, B.; van der Straten, P.; Beijerinck, H. C. W.; van Leeuwen, K. A. H.

    2002-01-01

    Laser focusing of Fe atoms offers the possibility of creating separate magnetic structures on a scale of 10 nm with exact periodicity. This can be done by using the parabolic minima of the potential generated by a standing light wave as focusing lenses. To achieve the desired 10-nm resolution, we need to suppress chromatic and spherical aberrations, as well as prevent structure broadening caused by the divergence of the incoming beam. Chromatic aberrations are suppressed by the development of a supersonic Fe beam source with speed ratio S = 11 ± 1. This beam has an intensity of 3 × 1015 atoms sr−1 s−1. The spherical aberrations of the standing light wave will be suppressed by aperturing with beam masks containing 100-nm slits at 744-nm intervals. The beam divergence can be reduced by application of laser cooling to reduce the transverse velocity. We have constructed a laser system capable of delivering over 500 mW of laser light at 372 nm, the wavelength of the 5D4 → 5F5 atomic transition of 56Fe we intend to use for laser cooling. Application of polarization spectroscopy to a hollow cathode discharge results in a locking system holding the laser continuously within 2 MHz of the desired frequency. PMID:11917133

  1. Magnetic nanodots from atomic Fe: can it be done?

    PubMed

    te Sligte, E; Bosch, R C M; Smeets, B; van der Straten, P; Beijerinck, H C W; van Leeuwen, K A H

    2002-04-30

    Laser focusing of Fe atoms offers the possibility of creating separate magnetic structures on a scale of 10 nm with exact periodicity. This can be done by using the parabolic minima of the potential generated by a standing light wave as focusing lenses. To achieve the desired 10-nm resolution, we need to suppress chromatic and spherical aberrations, as well as prevent structure broadening caused by the divergence of the incoming beam. Chromatic aberrations are suppressed by the development of a supersonic Fe beam source with speed ratio S = 11 +/- 1. This beam has an intensity of 3 x 10(15) atoms sr(-1) s(-1). The spherical aberrations of the standing light wave will be suppressed by aperturing with beam masks containing 100-nm slits at 744-nm intervals. The beam divergence can be reduced by application of laser cooling to reduce the transverse velocity. We have constructed a laser system capable of delivering over 500 mW of laser light at 372 nm, the wavelength of the (5)D(4) --> (5)F(5) atomic transition of (56)Fe we intend to use for laser cooling. Application of polarization spectroscopy to a hollow cathode discharge results in a locking system holding the laser continuously within 2 MHz of the desired frequency. PMID:11917133

  2. Design criteria for warm temperature dielectric superconducting dc cables: Impact of co-pole magnetic fields

    NASA Astrophysics Data System (ADS)

    Grant, P. M.; Hassenzahl, W. V.; Gregory, B.; Eckroad, S. W.

    2008-02-01

    HTSC dc superconducting cables are under consideration for a variety of applications ranging from bi-directional interties between regional ac grids ("back-to-backs"), internal connection within, and out-feeds from, low voltage solar or wind farm generators, and up to multi-gigawatt transmission trunks linking remote nuclear clusters to urban load centers. In every instance, there are two principal design choices - coaxial, or "cold temperature dielectric; and mono-axial, also termed "warm temperature dielectric." In the former, both poles may be serviced by concentric conductors in the same physical package, separated by insulation held at the temperature necessary for superconducting operation, and in the latter, the poles are contained in two separate cables of more or less conventional design, each holding a cryostat enclosing the superconductor surrounded by a dielectric material at ambient temperature. Both have "pluses and minuses." CTD has the advantage of compactness, but requires a cryogenic dielectric, whereas WTD is simpler to manufacture and less costly overall as well. However, depending on the dimensional separation of the two poles and their containment infrastructure, WTD can experience considerable outward compressive physical forces and some reduction in critical state properties due to interpenetration of their respective magnetic fields. Recent progress in introducing homogeneous pinning in YBCO coated conductors could considerably ameliorate this latter issue, and thus the WTD design could engage a range of applications formerly out of reach of BSCCO tapes. We will examine these two issues in detail.

  3. Reaching the magnetic anisotropy limit of a 3d metal atom.

    PubMed

    Rau, Ileana G; Baumann, Susanne; Rusponi, Stefano; Donati, Fabio; Stepanow, Sebastian; Gragnaniello, Luca; Dreiser, Jan; Piamonteze, Cinthia; Nolting, Frithjof; Gangopadhyay, Shruba; Albertini, Oliver R; Macfarlane, Roger M; Lutz, Christopher P; Jones, Barbara A; Gambardella, Pietro; Heinrich, Andreas J; Brune, Harald

    2014-05-30

    Designing systems with large magnetic anisotropy is critical to realize nanoscopic magnets. Thus far, the magnetic anisotropy energy per atom in single-molecule magnets and ferromagnetic films remains typically one to two orders of magnitude below the theoretical limit imposed by the atomic spin-orbit interaction. We realized the maximum magnetic anisotropy for a 3d transition metal atom by coordinating a single Co atom to the O site of an MgO(100) surface. Scanning tunneling spectroscopy reveals a record-high zero-field splitting of 58 millielectron volts as well as slow relaxation of the Co atom's magnetization. This striking behavior originates from the dominating axial ligand field at the O adsorption site, which leads to out-of-plane uniaxial anisotropy while preserving the gas-phase orbital moment of Co, as observed with x-ray magnetic circular dichroism. PMID:24812206

  4. Bose-Einstein condensation on a permanent-magnet atom chip

    SciTech Connect

    Sinclair, C.D.J.; Curtis, E.A.; Garcia, I. Llorente; Retter, J.A.; Hall, B. V.; Eriksson, S.; Sauer, B.E.; Hinds, E.A.

    2005-09-15

    We have produced a Bose-Einstein condensate on a permanent-magnet atom chip based on periodically magnetized videotape. We observe the expansion and dynamics of the condensate in one of the microscopic waveguides close to the surface. The lifetime for atoms to remain trapped near this dielectric material is significantly longer than above a metal surface of the same thickness. These results illustrate the suitability of microscopic permanent-magnet structures for quantum-coherent preparation and manipulation of cold atoms.

  5. Magnetic conveyor belt transport of ultracold atoms to a superconducting atomchip

    NASA Astrophysics Data System (ADS)

    Minniberger, Stefan; Diorico, Fritz; Haslinger, Stefan; Hufnagel, Christoph; Novotny, Christian; Lippok, Nils; Majer, Johannes; Koller, Christian; Schneider, Stephan; Schmiedmayer, Jörg

    2014-09-01

    We report the realization of a robust magnetic transport scheme to bring >3 × 108 ultracold 87Rb atoms into a cryostat. The sequence starts with standard laser cooling and trapping of 87Rb atoms, transporting first horizontally and then vertically through the radiation shields into a cryostat by a series of normal- and superconducting magnetic coils. Loading the atoms in a superconducting microtrap paves the way for studying the interaction of ultracold atoms with superconducting surfaces and quantum devices requiring cryogenic temperatures.

  6. Mapping magnetism with atomic resolution using aberrated electron probes

    NASA Astrophysics Data System (ADS)

    Idrobo, Juan; Rusz, Ján; McGuire, Michael A.; Symons, Christopher T.; Vatsavai, Ranga Raju; Lupini, Andrew R.

    2015-03-01

    In this talk, we report a direct experimental real-space mapping of magnetic circular dichroism with atomic resolution in aberration-corrected scanning transmission electron microscopy (STEM). Using an aberrated electron probe with customized phase distribution, we reveal with electron energy-loss (EEL) spectroscopy the checkerboard antiferromagnetic ordering of Mn moments in LaMnAsO by observing a dichroic signal in the Mn L-edge. The aberrated probes allow the collection of EEL spectra using the transmitted beam, which results in a magnetic circular dichroic signal with intrinsically larger signal-to-noise ratios than those obtained via nanodiffraction techniques (where most of the transmitted electrons are discarded). The novel experimental setup presented here, which can easily be implemented in aberration-corrected STEM, opens new paths for probing dichroic signals in materials with unprecedented spatial resolution. This research was supported by DOE SUFD MSED, by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US DOE, and by the Swedish Research Council and Swedish National Infrastructure for Computing (NSC center)

  7. Atomic spin resonance in a rubidium beam obliquely incident to a transmission magnetic grating

    NASA Astrophysics Data System (ADS)

    Hatakeyama, A.; Goto, K.

    2016-03-01

    We studied atomic spin resonance induced by atomic motion in a spatially periodic magnetostatic field. A rubidium atomic beam, with a velocity of about 400 m s-1, was obliquely incident to a transmission magnetic grating that produced a spatially periodic magnetic field. The magnetic grating was formed by a magnetic thin film on a polyimide substrate that had multiple slits at 150 μm intervals. The atoms experienced field oscillation, depending on their velocity and the field period when passing through the grating, and underwent magnetic resonance. Resonance spectra obtained with a perpendicular magnetization film were in clear contrast to ones obtained with an in-plane magnetization film. The former exhibited resonance peaks at odd multiples of the frequency, determined by the velocity over the period, while the latter had dips at the same frequencies.

  8. Magnetic levitation for effective loading of cold cesium atoms in a crossed dipole trap

    NASA Astrophysics Data System (ADS)

    Li, Yuqing; Feng, Guosheng; Xu, Rundong; Wang, Xiaofeng; Wu, Jizhou; Chen, Gang; Dai, Xingcan; Ma, Jie; Xiao, Liantuan; Jia, Suotang

    2015-05-01

    We report a detailed study of effective magnetically levitated loading of cold atoms in a crossed dipole trap: an appropriate magnetic field gradient precisely compensates for the destructive gravitational force of the atoms and an additional bias field simultaneously eliminates the antitrapping potential induced by the magnetic field gradient. The magnetic levitation is required for a large-volume crossed dipole trap to form a shallow but very effective loading potential, making it a promising method for loading and trapping more cold atoms. For cold cesium atoms in the F =3 , m F =3 state prepared by three-dimensional degenerated Raman sideband cooling, a large number of atoms ˜3.2 ×106 have been loaded into a large-volume crossed dipole trap with the help of the magnetic levitation technique. The dependence of the number of atoms loaded and trapped in the dipole trap on the magnetic field gradient and bias field, respectively, is in good agreement with the theoretical analysis. The optimum magnetic field gradient of 31.13 G/cm matches the theoretical value of 31.3 G/cm well. This method can be used to obtain more cold atoms or a large number of Bose-Einstein condensation atoms for many atomic species in high-field seeking states.

  9. Atomic site sensitivity of the energy loss magnetic chiral dichroic spectra of complex oxides

    SciTech Connect

    Calmels, L.; Rusz, J.

    2011-04-01

    The quantitative analysis of magnetic oxide core level spectra can become complicated when the magnetic atoms are located at several nonequivalent atomic sites in the crystal. This is, for instance, the case for Fe atoms in magnetite, which are located in tetrahedral and octahedral atomic sites; in this case, the x-ray magnetic circular dichroic (XMCD) spectra recorded at the L{sub 2,3} edge of Fe contain contributions from the different nonequivalent atomic sites, which unfortunately cannot be separated. Energy loss magnetic chiral dichroic (EMCD) spectra are the transmission electron microscope analogies of the XMCD spectra. One of the important differences between these two techniques of magnetic analysis is that EMCD uses a fast electron beam instead of polarized light. The fast electrons behave like Bloch states in the sample, and the fine structure of the EMCD spectra is strongly influenced by channeling and dynamical diffraction effects. These effects can be adjusted by changing the experimental configuration. We use theoretical calculations, which include dynamical diffraction effects and in which electronic transitions are treated in the atomic multiplet formalism, to show that the relative weight of the Fe atoms in different nonequivalent atomic sites can be changed by a proper choice of the position of the detector and of the magnetite sample orientation and thickness. We conclude that EMCD spectra could be used to isolate the magnetic contribution of atoms in each of the nonequivalent atomic sites, which would not be possible with XMCD techniques.

  10. Effect of magnetism and atomic order on static atomic displacements in the Invar alloy Fe-27 at.% Pt

    NASA Astrophysics Data System (ADS)

    Sax, C. R.; Schönfeld, B.; Ruban, A. V.

    2015-08-01

    Fe-27 at.% Pt was aged at 1123 K and quenched to room temperature (RT) to set up a state of thermal equilibrium. The local atomic arrangement was studied by diffuse x-ray scattering above (at 427 K) and below (at RT) the Curie temperature as well as at RT under a saturating magnetic field. The separated short-range order scattering remained unchanged for all three states, with maxima at 100 positions. Effective pair interaction parameters determined by the inverse Monte Carlo method gave an order-disorder transition temperature of about 1088 K, close to direct experimental findings. The species-dependent static atomic displacements for the first two shells show large differences, with a strong increase in magnitude from the state at 427 K over RT to the state under saturating magnetic field. This outcome is in agreement with an increase in atomic volume of Fe with increasing local magnetic moment. Electronic-structure calculations closely reproduce the values for the static atomic displacements in the ferromagnetic state, and predict their dependence on the atomic configuration. They also reveal a strong dependence of the magnetic exchange interactions in Fe-Pt on the atomic configuration state and lattice parameter. In particular, the increase of the Curie temperature in a random state relative to that in the ordered one is demonstrated to be related to the corresponding change of the magnetic exchange interactions due to the different local atomic chemical environment. There exists a similar strong concentration dependence of the chemical interactions as in the case of magnetic exchange interactions. Theoretical effective interactions for Fe-27 at.% Pt alloy are in good agreement with experimental results, and they also reproduce well the L1 2-A1 transition temperature.

  11. Magnetic excitations of rare earth atoms and clusters on metallic surfaces.

    PubMed

    Schuh, Tobias; Miyamachi, Toshio; Gerstl, Stefan; Geilhufe, Matthias; Hoffmann, Martin; Ostanin, Sergey; Hergert, Wolfram; Ernst, Arthur; Wulfhekel, Wulf

    2012-09-12

    Magnetic anisotropy and magnetization dynamics of rare earth Gd atoms and dimers on Pt(111) and Cu(111) were investigated with inelastic tunneling spectroscopy. The spin excitation spectra reveal that giant magnetic anisotropies and lifetimes of the excited states of Gd are nearly independent of the supporting surfaces and the cluster size. In combination with theoretical calculations, we argue that the observed features are caused by strongly localized character of 4f electrons in Gd atoms and clusters. PMID:22906055

  12. Engineering the magnetic anisotropy of atomic-scale nanostructure under electric field

    NASA Astrophysics Data System (ADS)

    Zhu, Wanjiao; Ding, Hang-Chen; Tong, Wen-Yi; Gong, Shi-Jing; Wan, Xiangang; Duan, Chun-Gang

    2015-02-01

    Atomic-scale magnetic nanostructures are promising candidates for future information processing devices. Utilizing external electric field to manipulate their magnetic properties is an especially thrilling project. Here, by carefully identifying the different contributions of each atomic orbital to the magnetic anisotropy energy (MAE) of the ferromagnetic metal films, we argue that it is possible to engineer both the MAE and the magnetic response to the electric field of atomic-scale magnetic nanostructures. Taking the iron monolayer as a matrix, we propose several interesting iron nanostructures with dramatically different magnetic properties. Such nanostructures could exhibit a strong magnetoelectric effect. Our work may open new avenues to the artificial design of electrically controlled magnetic devices.

  13. Effects of warm temper rolling on microstructure, texture and magnetic properties of strip-casting 6.5 wt% Si electrical steel

    NASA Astrophysics Data System (ADS)

    Li, Hao-Ze; Liu, Hai-Tao; Liu, Yi; Liu, Zhen-Yu; Cao, Guang-Ming; Luo, Zhong-Han; Zhang, Feng-Quan; Chen, Sheng-Lin; Lyu, Li; Wang, Guo-Dong

    2014-12-01

    6.5 wt% Si electrical steel thin sheets were produced by a processing route including strip casting, hot rolling, warm rolling, intermediate annealing, warm temper rolling and final annealing, in which the warm temper rolling reduction varied from 2.7% to 14.4%. A detailed study of the microstructural and textural evolutions through the whole processing route was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. The findings revealed that the final recrystallization microstructure, texture and magnetic properties relied heavily on the warm temper rolling reduction. As the warm temper rolling reduction increased from 2.7% to 14.4%, the finally recrystallized microstructures were more homogeneous and the average grain size was decreased. At the warm temper rolling reduction lower than 7.0%, the occurrence of the exaggeratedly large annealing grains which dominated the whole sheet thickness resulted in strong <001>//ND fiber, parallel α-fiber, <111>//ND fiber and many other strong hard-magnetization texture components. By contrast, at the warm temper rolling reduction higher than 7.0%, the recrystallization textures were characterized by weak <001>//ND fiber, parallel α-fiber, <111>//ND texture, together with fewer and weak hard-magnetization texture components. The mechanism responsible for the finally microstructural and textural changes was explained by strain induced boundary migration. As warm temper rolling reduction increased, the magnetic properties at high frequency were gradually improved due to smaller grain sizes and more desirable textures. The highest magnetic inductions of 1.383 T (B8), 1.484 T (B25) and 1.571 T (B50) in combination with the lowest iron losses at high frequencies of 19.11 W/Kg (W10/400) and 3.824 W/Kg (W2/1000) were obtained at 14.4% warm temper rolling reduction under the applied condition.

  14. Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO

    NASA Astrophysics Data System (ADS)

    Baumann, S.; Donati, F.; Stepanow, S.; Rusponi, S.; Paul, W.; Gangopadhyay, S.; Rau, I. G.; Pacchioni, G. E.; Gragnaniello, L.; Pivetta, M.; Dreiser, J.; Piamonteze, C.; Lutz, C. P.; Macfarlane, R. M.; Jones, B. A.; Gambardella, P.; Heinrich, A. J.; Brune, H.

    2015-12-01

    We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.0 ±0.3 meV /atom . This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment.

  15. Nanofiber-based atom trap created by combining fictitious and real magnetic fields

    NASA Astrophysics Data System (ADS)

    Schneeweiss, Philipp; Le Kien, Fam; Rauschenbeutel, Arno

    2014-01-01

    We propose a trap for cold neutral atoms using a fictitious magnetic field induced by a nanofiber-guided light field in conjunction with an external magnetic bias field. In close analogy to magnetic side-guide wire traps realized with current-carrying wires, a trapping potential can be formed when applying a homogeneous magnetic bias field perpendicular to the fiber axis. We discuss this scheme in detail for laser-cooled cesium atoms and find trap depths and trap frequencies comparable to the two-color nanofiber-based trapping scheme but with one order of magnitude lower power of the trapping laser field. Moreover, the proposed scheme allows one to bring the atoms closer to the nanofiber surface, thereby enabling efficient optical interfacing of the atoms with additional light fields. Specifically, optical depths per atom, σ0/Aeff, of more than 0.4 are predicted, making this system eligible for nanofiber-based nonlinear and quantum optics experiments.

  16. Origin of Perpendicular Magnetic Anisotropy and Large Orbital Moment in Fe Atoms on MgO.

    PubMed

    Baumann, S; Donati, F; Stepanow, S; Rusponi, S; Paul, W; Gangopadhyay, S; Rau, I G; Pacchioni, G E; Gragnaniello, L; Pivetta, M; Dreiser, J; Piamonteze, C; Lutz, C P; Macfarlane, R M; Jones, B A; Gambardella, P; Heinrich, A J; Brune, H

    2015-12-01

    We report on the magnetic properties of individual Fe atoms deposited on MgO(100) thin films probed by x-ray magnetic circular dichroism and scanning tunneling spectroscopy. We show that the Fe atoms have strong perpendicular magnetic anisotropy with a zero-field splitting of 14.0±0.3  meV/atom. This is a factor of 10 larger than the interface anisotropy of epitaxial Fe layers on MgO and the largest value reported for Fe atoms adsorbed on surfaces. The interplay between the ligand field at the O adsorption sites and spin-orbit coupling is analyzed by density functional theory and multiplet calculations, providing a comprehensive model of the magnetic properties of Fe atoms in a low-symmetry bonding environment. PMID:26684139

  17. Magnetic dipole-dipole sensing at atomic scale using electron spin resonance STM

    NASA Astrophysics Data System (ADS)

    Choi, T.; Paul, W.; Rolf-Pissarczyk, S.; MacDonald, A.; Yang, K.; Natterer, F. D.; Lutz, C. P.; Heinrich, A. J.

    Magnetometry having both high magnetic field sensitivity and atomic resolution has been an important goal for applications in diverse fields covering physics, material science, and biomedical science. Recent development of electron spin resonance STM (ESR-STM) promises coherent manipulation of spins and studies on magnetic interaction of artificially built nanostructures, leading toward quantum computation, simulation, and sensors In ESR-STM experiments, we find that the ESR signal from an Fe atom underneath a STM tip splits into two different frequencies when we position an additional Fe atom nearby. We measure an ESR energy splitting that decays as 1/r3 (r is the separation of the two Fe atoms), indicating that the atoms are coupled through magnetic dipole-dipole interaction. This energy and distance relation enables us to determine magnetic moments of atoms and molecules on a surface with high precision in energy. Unique and advantageous aspects of ESR-STM are the atom manipulation capabilities, which allow us to build atomically precise nanostructures and examine their interactions. For instance, we construct a dice cinque arrangement of five Fe atoms, and probe their interaction and energy degeneracy. We demonstrate the ESR-STM technique can be utilized for quantum magnetic sensors.

  18. Atoms in Strong Magnetic Fields. Quantum Mechanical Treatment and Applications in Astrophysics and Quantum Chaos

    NASA Astrophysics Data System (ADS)

    Ruder, Hanns; Wunner, Günter; Herold, Heinz; Geyer, Florian

    This book serves both students and researchers. It gives a clear and accessible introduction to quantum mechanical methods used to calculate properties of atoms exposed to strong magnetic fields in both laboratory and stellar environments. The results of the detailed calculations are listed in tables, making it a useful handbook for astrophysicists and atomic physicists alike. The emphasis is on hydrogen and helium and their isoelectronic sequences. Important applications are highlighted: the interpretation of the spectra of strongly magnetic white dwarf stars, and the prominent role of atoms in strong magnetic fields in studies of quantum chaos.

  19. Simultaneous differential measurement of a magnetic-field gradient by atom interferometry using double fountains

    SciTech Connect

    Hu Zhongkun; Duan Xiaochun; Zhou Minkang; Sun Buliang; Zhao Jinbo; Huang Maomao; Luo Jun

    2011-07-15

    Precisely measuring the magnetic-field gradient within a vacuum chamber is important for many precision experiments and can be realized by atom interferometry using magnetically sensitive sublevels at different times to make a differential measurement, which had been demonstrated in our previous work. In this paper, we demonstrate a differential method to measure the magnetic-field gradient by means of two simultaneously operated atom interferometers using double atomic fountains. By virtue of this simultaneous differential measurement to reject common-mode noise, the resolution can be improved by one order of magnitude for about a 1000-s integration time.

  20. Design of a millimetre-scale magnetic surface trap for cold atoms

    NASA Astrophysics Data System (ADS)

    Trypogeorgos, D.; Albright, S. D.; Beesley, D.; Foot, C. J.

    2014-04-01

    We study a novel millimetre-scale magnetic trap for ultracold atoms, in which the current carrying conductors can be situated outside the vacuum region, a few mm away from the atoms. This design generates a magnetic field gradient in excess of 1000 G cm-1 at a distance of 2 mm from the conductors. We perform electromagnetic and thermo-mechanical characterization using finite element methods. The predicted behaviour has been verified by electrical and thermal measurements on a prototype, but has not been implemented on an apparatus with cold atoms. Operating this trap at the highest gradient allows rapid evaporative cooling comparable to that achieved by atom chips.

  1. Ultracold atoms in microfabricated magnetic traps near surfaces and inside optical resonators

    NASA Astrophysics Data System (ADS)

    Teper, Igor

    Microfabricated magnetic traps ("microtraps") for ultracold atoms allow the creation of complex, precisely-controlled, and sharply-varying potentials that hold great promise for a variety of new quantum devices for atomic matter waves. We present two experiments that examine the capabilities and also the fundamental limits of microtraps. In the first experiment, we investigate the stability of magnetically trapped Bose-Einstein condensates and thermal clouds near the transition temperature at distances of 0.5--10 microns from a microfabricated silicon chip. Near a copper film, the trap lifetime is limited by spin flips due to the coupling of the atoms' electronic spins to magnetic field fluctuations produced by the thermal motion of electrons in the copper (Johnson noise). We present a simple formula that can account for this observed loss process with no free parameters. A dielectric surface has no adverse effect on the trapped atoms until they are brought so close to the surface that the attractive Casimir-Polder potential reduces the trap depth, which leads to loss of atoms. In the second experiment, we implement sensitive atom detection for atoms in the microtrap through the use of a medium-finesse, macroscopic optical resonator integrated with the chip. As detection methods, we employ both fluorescence into the cavity and atom-induced reduction in cavity transmission. In fluorescence, we register 2.0 photon counts per atom, which allows us to detect single atoms with 75% efficiency in 250 mus. In absorption, we measure transmission attenuation of 3.3% per atom, which allows us to count small numbers of atoms with a resolution of about 1 atom. We also demonstrate shot-noise-limited atom preparation down to 1 atom.

  2. Designing and building a permanent magnet Zeeman slower for calcium atoms using a 3D printer

    NASA Astrophysics Data System (ADS)

    Parsagian, Alexandria; Kleinert, Michaela

    2015-10-01

    We present the design of a Zeeman slower for calcium atoms using permanent magnets instead of more traditional electromagnets and the novel technique of 3D printing to create a very robust and flexible structure for these magnets. Zeeman slowers are ideal tools to slow atoms from several hundreds of meters per second to just a few tens of meters per second. These slower atoms can then easily be trapped in a magneto-optical trap, making Zeeman slowers a very valuable tool in many cold atom labs. The use of permanent magnets and 3D printing results in a highly stable and robust slower that is suitable for undergraduate laboratories. In our design, we arranged 28 magnet pairs, 2.0 cm apart along the axis of the slower and at varying radial distances from the axis. We determined the radial position of the magnets by simulating the combined field of all magnet pairs using Mathematica and comparing it to the ideal theoretical field for a Zeeman slower. Finally, we designed a stable, robust, compact, and easy-to-align mounting structure for the magnets in Google Sketchup, which we then printed using a commercially available 3D printer by Solidoodle. The resulting magnetic field is well suited to slow calcium atoms from the 770 m/s rms velocity at a temperature of 950 K, down to the capture velocity of the magneto-optical trap.

  3. Effects of AC magnetic field on spin-exchange relaxation of atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Lu, Jixi; Qian, Zheng; Fang, Jiancheng; Quan, Wei

    2016-03-01

    By operating at high alkali-metal densities and in low magnetic fields, the spin-exchange relaxation of atomic magnetometers can be eliminated, allowing construction of ultra-high sensitive spin-exchange relaxation-free magnetometers. Significant AC magnetic fields are usually introduced in the magnetometer by the magnetic field modulation technique or the cell heater, whose effects on the spin-exchange relaxation have not been evaluated. In this paper, we study experimentally the spin-exchange relaxation rate as a function of the magnetic field frequency, the magnetic field amplitude and the spin-exchange rate in low magnetic fields. The experimental results indicate that for low atomic polarization the spin-exchange relaxation rate decays exponentially with the magnetic field frequency, and the reciprocal of the decay constant is proportional to the spin-exchange rate.

  4. The Saga of Light-Matter Interaction and Magneto-optical Effects Applications to Atomic Magnetometry, Laser-cooled Atoms, Atomic Clocks, Geomagnetism, and Plant Bio-magnetism

    NASA Astrophysics Data System (ADS)

    Corsini, Eric P.

    The quest to expand the limited sensorial domain, in particular to bridge the inability to gauge magnetic fields near and far, has driven the fabrication of remedial tools. The interaction of ferromagnetic material with a magnetic field had been the only available technique to gauge that field for several millennium. The advent of electricity and associated classical phenomena captured in the four Maxwell equations, were a step forward. In the early 1900s, the model of quantum mechanics provided a two-way leap forward. One came from the newly understood interaction of light and matter, and more specifically the three-way coupling of photons, atoms' angular momenta, and magnetic field, which are the foundations of atomic magnetometry. The other came from magnetically sensitive quantum effects in a fabricated energy-ladder form of matter cooled to a temperature below that of the energy steps; these quantum effects gave rise to the superconducting quantum interference device (SQUID). Research using atomic magnetometers and SQUIDs has resulted in thousands of publications, text books, and conferences. The current status in each field is well described in Refs. [48,49,38,42] and all references therein. In this work we develop and investigate techniques and applications pertaining to atomic magnetometry. [Full text: eric.corsini gmail.com].

  5. Decoherence-governed magnetic-moment dynamics of supported atomic objects

    NASA Astrophysics Data System (ADS)

    Gauyacq, Jean-Pierre; Lorente, Nicolás

    2015-11-01

    Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196-9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system’s size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching.

  6. The UKB prescription and the heavy atom effects on the nuclear magnetic shielding of vicinal heavy atoms.

    PubMed

    Maldonado, Alejandro F; Aucar, Gustavo A

    2009-07-21

    Fully relativistic calculations of NMR magnetic shielding on XYH3 (X = C, Si, Ge and Sn; Y = Br, I), XHn (n = 1-4) molecular systems and noble gases performed with a fully relativistic polarization propagator formalism at the RPA level of approach are presented. The rate of convergence (size of basis set and time involved) for calculations with both kinetic balance prescriptions, RKB and UKB, were investigated. Calculations with UKB makes it feasible to obtain reliable results for two or more heavy-atom-containing molecules. For such XYH3 systems, the influence of heavy vicinal halogen atoms on sigma(X) is such that heavy atom effects on heavy atoms (vicinal plus their own effects or HAVHA + HAHA effects) amount to 30.50% for X = Sn and Y = I; being the HAHA effect of the order of 25%. So the vicinal effect alone is of the order of 5.5%. The vicinal heavy atom effect on light atoms (HALA effect) is of the order of 28% for X = C and Y = I. A similar behaviour, but of opposite sign, is observed for sigma(Y) for which sigmaR-NR (I; X = C) (HAHA effect) is around 27% and sigmaR-NR(I; X = Sn) (HAVHA + HAHA effects) is close to 21%. Its electronic origin is paramagnetic for halogen atoms but both dia- and paramagnetic for central atoms. The effect on two bond distant hydrogen atoms is such that the largest variation of sigma(H) within the same family of XYH3 molecules appears for X = Si and Y = I: around 20%. In this case sigma(H; X = Sn, Y = I) = 33.45 ppm and sigma(H; X = Sn, Y = H) = 27.82 ppm. PMID:19842479

  7. Fine structure in a strong magnetic field: Paschen-Back effect reconsidered in Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Liu, Wenyu; Gu, Sihong; Li, Baiwen

    1996-05-01

    Using a kind of potential model wave function for alkali metal atoms, we nonperturbatively study the effect of fine structure on the Rydberg spectra of Cs atom in a strong magnetic field. Our numerical results reveal spectral structure dramatically different from the well-established Paschen-Back effect, and we argue that the fine structure of the Rydberg Cs atom cannot be neglected even in a magnetic field as strong as several teslas. We also give an error estimate of our results and a word on possible experimental verification.

  8. Circular Rydberg States of Atomic Hydrogen in an Arbitrary Magnetic Field

    NASA Astrophysics Data System (ADS)

    Zhao, Li-Bo; B. C., Saha; Du, Meng-Li

    2011-09-01

    We report a theoretical scheme using a B-spline basis set to improve the poor computational accuracy of circular Rydberg states of hydrogen atoms in the intermediate magnetic field. This scheme can produce high accuracy energy levels and valid for an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers |m| = 10-70 as a function of magnetic field strengths ranging from zero to 2.35 × 109 T. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated.

  9. Bidirectional propagation of cold atoms in a 'stadium'-shaped magnetic guide

    SciTech Connect

    Wu Saijun; Rooijakkers, Wilbert; Striehl, Pierre; Prentiss, Mara

    2004-07-01

    We demonstrate the bidirectional propagation of more than 10{sup 7} atoms ({sup 87}Rb) around a 'stadium'-shaped magnetic ring that encloses an area of 10.9 cm{sup 2}, with a flux density exceeding 10{sup 11} atom s{sup -1} cm{sup -2}. Atoms are loaded into the guide from a two-dimensional (and higher) magneto-optical trap at one side of the 'stadium'. An optical standing wave pulse is applied to increase the propagation velocity of atoms along the waveguide. The atom sample fills the entire ring in 200 ms when counterpropagating atom sections of the original atom cloud recombine at their initial positions after a full revolution.

  10. Magnetic state selection in atomic frequency and time standards. [hydrogen masers

    NASA Technical Reports Server (NTRS)

    Peters, H. E.

    1982-01-01

    Atomic standards such as those based upon cesium and hydrogen rely upon magnetic state selection to obtain population inversion in the hyperfine transition levels. Use of new design approaches and improved magnetic materials has made it possible to fabricate improved state selectors of small size, and thus the efficiency of utilization of beam flux is greatly improved and the size and weight of the standard is reduced. The sensitivity to magnetic perturbations is also decreased, so that the accuracy and stability of the standard is improved. Several new state selector designs are illustrated and the application to standards utilizing different atomic species is analyzed.

  11. Monte Carlo simulation of a cesium atom beam in a magnetic field

    SciTech Connect

    Chen, Jiang Zhu, Hongwei; Ma, Yinguang; Li, Detian; Liu, Zhidong; Wang, Ji

    2015-03-07

    We present Monte Carlo simulations of the deflection of a beam of {sup 133}Cs atoms in a two wire magnetic field. Our results reveal the relationship between transmission rate of the atoms and incident parameters. Incident angle and position of the beam with maximum transmission are obtained from the simulations. The effect of the deflection field on the spatial distribution (beam profile) of {sup 133}Cs is derived. The method will help with the design of magnetic deflection experiments and to extract the magnetic properties from such experiments.

  12. In situ triaxial magnetic field compensation for the spin-exchange-relaxation-free atomic magnetometer.

    PubMed

    Fang, Jiancheng; Qin, Jie

    2012-10-01

    The spin-exchange-relaxation-free (SERF) atomic magnetometer is an ultra-high sensitivity magnetometer, but it must be operated in a magnetic field with strength less than about 10 nT. Magnetic field compensation is an effective way to shield the magnetic field, and this paper demonstrates an in situ triaxial magnetic field compensation system for operating the SERF atomic magnetometer. The proposed hardware is based on optical pumping, which uses some part of the SERF atomic magnetometer itself, and the compensation method is implemented by analyzing the dynamics of the atomic spin. The experimental setup for this compensation system is described, and with this configuration, a residual magnetic field of strength less than 2 nT (±0.38 nT in the x axis, ±0.43 nT in the y axis, and ±1.62 nT in the z axis) has been achieved after compensation. The SERF atomic magnetometer was then used to verify that the residual triaxial magnetic fields were coincident with what were achieved by the compensation system. PMID:23126748

  13. Magnetic-field-tunable Kondo effect in alkaline-earth cold atoms

    NASA Astrophysics Data System (ADS)

    Isaev, Leonid; Rey, Ana Maria

    We study quantum magnetism and emergent Kondo physics in strongly interacting fermionic alkaline-earth atoms in an optical lattice with two Bloch bands: one localized and one itinerant. For a fully filled narrow band (two atoms per lattice site) we demonstrate that an applied magnetic field provides an efficient control of the ground state degeneracy due to the field-induced crossing of singlet and triplet state of the localized atomic pairs. We exploit this singlet-triplet resonance, as well as magnetically tunable interactions of atoms in different electronic states via the recently-discovered inter-orbital Feshbach resonance, and demonstrate that the system exhibits a magnetic field-induced Kondo phase characterized by delocalization of local singlets and a large Fermi surface. We also determine the phase diagram of the system within an effective low-energy model that incorporates the above magnetic-field effect as well as atomic interactions in the two optical lattice bands. Our results can be tested with ultracold 173 Yb , and provide a model for the magnetic field-induced heavy-fermion state in filled skutterudites such as PrOs4Sb12 . This work was supported by the NSF (PIF-1211914 and PFC-1125844), AFOSR, AFOSR-MURI, NIST and ARO individual investigator awards.

  14. Precisely mapping the magnetic field gradient in vacuum with an atom interferometer

    SciTech Connect

    Zhou Minkang; Hu Zhongkun; Duan Xiaochun; Sun Buliang; Zhao Jinbo; Luo Jun

    2010-12-15

    The magnetic field gradient has been measured with an atom interferometer using the magnetic sublevels of {sup 87}Rb atoms. The Doppler-insensitive measurement effectively eliminates the contribution from gravity and background vibration noise, and the differential measurement also can reject some systematic errors. A resolution of 300 pT/mm has been demonstrated with a 90-s integration time and a spatial resolution of 1.4 mm. The gradiometer was then used to measure the magnetic field gradient in an ultrahigh-vacuum environment. The technique will also be very useful to subtract the systematic error arising from the magnetic field inhomogeneity in precision atom-interferometry experiments, such as gravity measurement.

  15. Chiral symmetries and Majorana fermions in coupled magnetic atomic chains on a superconductor

    NASA Astrophysics Data System (ADS)

    Xiao, Jinpeng; An, Jin

    2015-11-01

    We study the magnetic structures and their connections with topological superconductivity due to the proximity effect for coupled magnetic atomic chains deposited on a superconductor. Several magnetic phases are self-consistently determined, including both the coplanar and noncoplanar ones. For an N-chain triangular atomic ladder, topologically nontrivial superconducting states can always be realized, but strongly depend on its magnetic structure and the number of atomic chains. When N is even, the topologically nontrivial states with noncoplanar structures are characterized by {{{Z}}}2 invariants, while the topologically nontrivial noncoplanar states with an odd N are characterized by integer {{Z}} invariants, due to the presence of a new chiral symmetry. The new chiral symmetry for the noncoplanar states is found to be robust against the on-site disorder, as long as the crystal reflection symmetry is respected.

  16. Stray magnetic field compensation with a scalar atomic magnetometer.

    PubMed

    Belfi, J; Bevilacqua, G; Biancalana, V; Cecchi, R; Dancheva, Y; Moi, L

    2010-06-01

    We describe a system for the compensation of time-dependent stray magnetic fields using a dual channel scalar magnetometer based on nonlinear Faraday rotation in synchronously optically pumped Cs vapor. We detail the active control strategy, with an emphasis on the electronic circuitry, based on a simple phase-locked-loop integrated circuit. The performance and limits of the system developed are tested and discussed. The system was applied to significantly improve the detection of free induction decay signals from protons of remotely magnetized water precessing in an ultralow magnetic field. PMID:20590265

  17. A compact design for a magnetic synchrotron to store beams of hydrogen atoms

    NASA Astrophysics Data System (ADS)

    van der Poel, Aernout P. P.; Dulitz, Katrin; Softley, Timothy P.; Bethlem, Hendrick L.

    2015-05-01

    We present a design for an atomic synchrotron consisting of 40 hybrid magnetic hexapole lenses arranged in a circle. We show that for realistic parameters, hydrogen atoms with a velocity up to 600 m s-1 can be stored in a 1 m diameter ring, which implies that the atoms can be injected in the ring directly from a pulsed supersonic beam source. This ring can be used to study collisions between stored hydrogen atoms and supersonic beams of many different atoms and molecules. The advantage of using a synchrotron is two-fold: (i) the collision partners move in the same direction as the stored atoms, resulting in a small relative velocity and thus a low collision energy, and (ii) by storing atoms for many round-trips, the sensitivity to collisions is enhanced by a factor of 100-1000. In the proposed ring, the cross-sections for collisions between hydrogen, the most abundant atom in the universe, with any atom or molecule that can be put in a beam, including He, H2, CO, ammonia and OH can be measured at energies below 100 K. We discuss the possibility of using optical transitions to load hydrogen atoms into the ring without influencing the atoms that are already stored. In this way it will be possible to reach high densities of stored hydrogen atoms.

  18. Atomic structure, alloying behavior, and magnetism in small Fe-Pt clusters

    NASA Astrophysics Data System (ADS)

    Chittari, Bheema Lingam; Kumar, Vijay

    2015-09-01

    We report results of the atomic structure, alloying behavior, and magnetism in F emP tn(m +n =2 -10 ) clusters using projector augmented wave (PAW) pseudopotential method and spin-polarized generalized gradient approximation (GGA) for the exchange-correlation energy. These results are compared with those obtained by using HCTH exchange-correlation functional and LANL2DZ basis set in the Gaussian program and the overall trends are found to be similar. As in bulk Fe-Pt alloys, clusters with equal composition of Fe and Pt have the largest binding energy and the largest heat of nanoalloy formation for a given number of atoms in the cluster. There are some deviations due to the different symmetries in clusters and in cases where the total number of atoms is odd. The lowest energy isomers tend to maximize bonds between unlike atoms with Fe (Pt) atoms occupying high (low) coordination sites in the core (surface) of the cluster. The binding energy, heat of formation, and the second order difference of the total energy show F e2P t2 , F e4P t4 , and F e4P t6 clusters to be the most stable ones among the different clusters we have studied. The magnetic moments on Fe atoms are high in Pt-rich clusters as well as in small Fe-rich clusters and decrease as the aggregation of Fe atoms and the cluster size increases. The maximum value of the magnetic moments on Fe atoms is ˜3.8 μB , whereas for Pt atoms it is 1 μB. These are quite high compared with the values for bulk Fe as well as bulk FePt and F e3Pt phases while bulk Pt is nonmagnetic. There is significant charge transfer from those Fe atoms that interact directly with Pt atoms. We discuss the hybridization between the electronic states of Pt and Fe atoms as well as the variation in the magnetic moments on Fe and Pt atoms. Our results provide insight into the understanding of the nanoalloy behavior of Fe-Pt and we hope that this would help to design Fe based nanoalloys and their assemblies with high magnetic moments for strong magnets without rare earths as well as Pt alloy catalysts.

  19. Optical control of the spin of a magnetic atom in a semiconductor quantum dot

    NASA Astrophysics Data System (ADS)

    Besombes, L.; Boukari, H.; Le Gall, C.; Brunetti, A.; Cao, C. L.; Jamet, S.; Varghese, B.

    2015-04-01

    The control of single spins in solids is a key but challenging step for any spin-based solid-state quantumcomputing device. Thanks to their expected long coherence time, localized spins on magnetic atoms in a semiconductor host could be an interesting media to store quantum information in the solid state. Optical probing and control of the spin of individual or pairs of Manganese (Mn) atoms (S = 5/2) have been obtained in II-VI and IIIV semiconductor quantum dots during the last years. In this paper, we review recently developed optical control experiments of the spin of an individual Mn atoms in II-VI semiconductor self-assembled or strain-free quantum dots (QDs).We first show that the fine structure of the Mn atom and especially a strained induced magnetic anisotropy is the main parameter controlling the spin memory of the magnetic atom at zero magnetic field. We then demonstrate that the energy of any spin state of a Mn atom or pairs of Mn atom can be independently tuned by using the optical Stark effect induced by a resonant laser field. The strong coupling with the resonant laser field modifies the Mn fine structure and consequently its dynamics.We then describe the spin dynamics of a Mn atom under this strong resonant optical excitation. In addition to standard optical pumping expected for a resonant excitation, we show that the Mn spin population can be trapped in the state which is resonantly excited. This effect is modeled considering the coherent spin dynamics of the coupled electronic and nuclear spin of the Mn atom optically dressed by a resonant laser field. Finally, we discuss the spin dynamics of a Mn atom in strain-free QDs and show that these structures should permit a fast optical coherent control of an individual Mn spin.

  20. Control and manipulation of magnetic nanoparticles and cold atoms using micro-electromagnets

    NASA Astrophysics Data System (ADS)

    Lee, Chungsok

    We have developed micro-electromagnets to control and manipulate both ultra cold neutral atoms in vacuum and magnetic nanoparticles in a fluid. The design and fabrication of these micro-electromagnets are described. We then demonstrate the manipulation of atoms, magnetic nanoparticles, and magnetotactic bacteria using these micro-electromagnets. This thesis consists of two main parts: atom manipulation using planar micro-electromagnet guides, and magnetic particle manipulation using various multi-layer micro-electromagnets. We have designed, fabricated and experimentally demonstrated a microelectromagnet to guide atoms above a substrate. Micro-electromagnet guides consist of current carrying wires microfabricated on a flat substrate to produce two-dimensional magnetic field minimum that can control the trajectories of cold neutral atoms. Micro-electromagnets can produce magnetic field magnitudes to 0.1 T with field gradients to |∇B| ˜ 104 T/cm because high currents can be applied to microfabricated wires with current densities up to 5 x 107A/cm2. Magnetic field calculations show that the structure of a micro-electromagnet needs to be carefully designed to optimize the loading of atoms into the micro-electromagnet. Experimental results are discussed that demonstrate the guiding of atoms. We discuss the design of new micro- and nano-electromagnets that may be used as beam splitter and interferometer for atoms. We have also demonstrated the ability of micro-electromagnets to trap, move and assemble magnetic nanoparticles and magnetotactic bacteria in a fluid above a substrate at room temperature. Two types of micro-electromagnets, a ring trap and a matrix, have been fabricated. The ring trap is a single circular Au wire with a smooth insulating layer on top. A ring trap has been demonstrated to trap magnetic particles and magnetotactic bacteria at fixed positions. The matrix consists of two arrays of lithographically patterned Au wires, separated by an insulating layer with a smooth insulating layer on top. By controlling the currents through individual wires, the matrix can produce single or multiple peaks in the magnetic field magnitude that can be continuously moved across the surface to any position, with spatial resolution much less than the wire spacing. Using a matrix, we have trapped and moved magnetic particles and magnetotactic bacteria over the surface. We have also rotated magnetic particles above a fixed position in microscopic region utilizing time-dependent current control. Possibilities to manipulate single nanoparticles using nano-electromagnets are discussed.

  1. Three-electron atoms and ions in a magnetic field

    NASA Astrophysics Data System (ADS)

    Salas, J. A.; Pelaschier, I.; Varga, K.

    2015-09-01

    The energies and physical properties of three-electron systems are studied using an explicitly correlated Gaussian basis optimized by the stochastic variational method. The stability of the system as a function of the nuclear charge is analyzed. The role of the Coulomb and magnetic interactions in shaping the structure of these systems is discussed. The accuracy of the energies is substantially improved for high magnetic fields.

  2. Circular Rydberg states of atomic hydrogen in an arbitrary magnetic field

    NASA Astrophysics Data System (ADS)

    Zhao, L. B.; Saha, B. C.; Du, M. L.

    2011-05-01

    A theoretical method using a B-spline basis set has been proposed to evaluate circular Rydberg states of atomic hydrogen in a strong magnetic field. The combination of this method and a recently reported finite-basis-set technique can provide a practicable scheme to implement high accuracy computations of circular Rydberg states of atomic hydrogen in an arbitrary magnetic field. Energy levels of hydrogen are presented for circular Rydberg states with azimuthal quantum numbers |m | = 10 - 70 as a function of magnetic field strengths ranging from zero to 2.35 × 109 T. Comparison with available theoretical data shows excellent agreement. The variation of spatial distributions of electron probability densities with magnetic field strengths is discussed and competition between Coulomb and magnetic interactions is illustrated. Supported by NSF-CREST project (grant #0630370).

  3. Magnetic merging of ultracold atomic gases of {sup 85}Rb and {sup 87}Rb

    SciTech Connect

    Haendel, S.; Wiles, T. P.; Marchant, A. L.; Hopkins, S. A.; Adams, C. S.; Cornish, S. L.

    2011-05-15

    We report the magnetic merging of ultracold atomic gases of {sup 85}Rb and {sup 87}Rb by the controlled overlap of two initially spatially separated magnetic traps. We present a detailed analysis of the combined magnetic-field potential as the two traps are brought together that predicts a clear optimum trajectory for the merging. We verify this prediction experimentally using {sup 85}Rb and find that the final atom number in the merged trap is maximized with minimal heating by following the predicted optimum trajectory. Using the magnetic-merging approach allows us to create variable-ratio isotopic Rb mixtures with a single laser-cooling setup by simply storing one isotope in a magnetic trap before jumping the laser frequencies to the transitions necessary to laser cool the second isotope.

  4. Magnetic-field-induced enhancement of atomic stabilization in intense high-frequency laser fields

    NASA Astrophysics Data System (ADS)

    Simonsen, Aleksander Skjerlie; Frre, Morten

    2015-07-01

    The role of the magnetic-field component of the laser pulse on the phenomenon of atomic stabilization is investigated in an ab initio study. This is achieved by solving the time-dependent Schrdinger equation for the laser-atom interaction beyond the dipole approximation. The system under study is atomic hydrogen and the atom is assumed to be irradiated by an intense xuv laser light pulse of varying intensity and duration. We consider two different photon energies, ? ? =54 and 95 eV. The main finding is that there exists a range of laser pulse durations lasting for a few tens of field cycles where the atomic stabilization effect is enhanced due to the magnetic-field component. This is a rather surprising result that contradicts earlier statements made in the few-cycle pulse regime, where it has been shown that the magnetic field has a destructive effect in that the degree of stabilization is suppressed. It is further found that in the long-pulse limit the ionization probabilities obtained when illuminating the target with dipole and nondipole fields eventually coincide, meaning that the magnetic-field component of the laser field finally loses its significance in the context of atomic stabilization. It is also found that within the window of enhanced stabilization, the surplus population is distributed among excited bound states rather than in the initial ground state.

  5. Electronic structures and magnetic properties of rare-earth-atom-doped BNNTs

    NASA Astrophysics Data System (ADS)

    Ren, Juan; Zhang, Ning-Chao; Wang, Peng; Ning, Chao; Zhang, Hong; Peng, Xiao-Juan

    2016-04-01

    Stable geometries, electronic structures, and magnetic properties of (8,0) and (4,4) single-walled BN nanotubes (BNNTs) doped with rare-earth (RE) atoms are investigated using the first-principles pseudopotential plane wave method with density functional theory (DFT). The results show that these RE atoms can be effectively doped in BNNTs with favorable energies. Because of the curvature effect, the values of binding energy for RE-atom-doped (4,4) BNNTs are larger than those of the same atoms on (8,0) BNNTs. Electron transfer between RE-5 d, 6 s, and B-2 p, N-2 p orbitals was also observed. Furthermore, electronic structures and magnetic properties of BNNTs can be modified by such doping. The results show that the adsorption of Ce, Pm, Sm, and Eu atoms can induce magnetization, while no magnetism is observed when BNNTs are doped with La. These results are useful for spintronics applications and for developing magnetic nanostructures.

  6. Realizing exactly solvable SU (N ) magnets with thermal atoms

    NASA Astrophysics Data System (ADS)

    Beverland, Michael E.; Alagic, Gorjan; Martin, Michael J.; Koller, Andrew P.; Rey, Ana M.; Gorshkov, Alexey V.

    2016-05-01

    We show that n thermal fermionic alkaline-earth-metal atoms in a flat-bottom trap allow one to robustly implement a spin model displaying two symmetries: the Sn symmetry that permutes atoms occupying different vibrational levels of the trap and the SU (N ) symmetry associated with N nuclear spin states. The symmetries make the model exactly solvable, which, in turn, enables the analytic study of dynamical processes such as spin diffusion in this SU (N ) system. We also show how to use this system to generate entangled states that allow for Heisenberg-limited metrology. This highly symmetric spin model should be experimentally realizable even when the vibrational levels are occupied according to a high-temperature thermal or an arbitrary nonthermal distribution.

  7. Ultra-sensitive Magnetic Microscopy with an Atomic Magnetometer

    SciTech Connect

    Kim, Young Jin

    2015-08-19

    The PowerPoint presentation focused on research goals, specific information about the atomic magnetometer, response and resolution factors of the SERF magnetometer, FC+AM systems, tests of field transfer and resolution on FC, gradient cancellation, testing of AM performance, ideas for a multi-channel AM, including preliminary sensitivity testing, and a description of a 6 channel DAQ system. A few ideas for future work ended the presentation.

  8. Atomic-Scale Interfacial Magnetism in Fe/Graphene Heterojunction

    PubMed Central

    Liu, W. Q.; Wang, W. Y.; Wang, J. J.; Wang, F. Q.; Lu, C.; Jin, F.; Zhang, A.; Zhang, Q. M.; Laan, G. van der; Xu, Y. B.; Li, Q. X.; Zhang, R.

    2015-01-01

    Successful spin injection into graphene makes it a competitive contender in the race to become a key material for quantum computation, or the spin-operation-based data processing and sensing. Engineering ferromagnetic metal (FM)/graphene heterojunctions is one of the most promising avenues to realise it, however, their interface magnetism remains an open question up to this day. In any proposed FM/graphene spintronic devices, the best opportunity for spin transport could only be achieved where no magnetic dead layer exists at the FM/graphene interface. Here we present a comprehensive study of the epitaxial Fe/graphene interface by means of X-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations. The experiment has been performed using a specially designed FM1/FM2/graphene structure that to a large extent restores the realistic case of the proposed graphene-based transistors. We have quantitatively observed a reduced but still sizable magnetic moments of the epitaxial Fe ML on graphene, which is well resembled by simulations and can be attributed to the strong hybridization between the Fe 3dz2 and the C 2pz orbitals and the sp-orbital-like behavior of the Fe 3d electrons due to the presence of graphene. PMID:26145155

  9. Velocity-selected magnetic guiding of Zeeman-decelerated hydrogen atoms

    NASA Astrophysics Data System (ADS)

    Dulitz, Katrin; Softley, Timothy P.

    2016-01-01

    An original design of magnetic guide is presented, suitable for use with Zeeman-decelerated supersonic beams of ground-state hydrogen atoms and other light paramagnetic species. Three-dimensional particle trajectory simulations show that, by combining a series of permanent-magnet Halbach arrays with pulsed high-current wire electromagnets, this guide can be used to efficiently transmit the slow, decelerated atoms and discard the faster, undecelerated atoms and other species in the gas beam. The curved guide would be suitable for guiding hydrogen atoms into an ion trap to investigate low temperature ion-molecule collisions. It is also shown that the device could be used for the guiding or velocity selection from an undecelerated supersonic or effusive beam.

  10. Magnetic induction tomography using an all-optical ⁸⁷Rb atomic magnetometer.

    PubMed

    Wickenbrock, Arne; Jurgilas, Sarunas; Dow, Albert; Marmugi, Luca; Renzoni, Ferruccio

    2014-11-15

    We demonstrate magnetic induction tomography (MIT) with an all-optical atomic magnetometer. Our instrument creates a conductivity map of conductive objects. Both the shape and size of the imaged samples compare very well with the actual shape and size. Given the potential of all-optical atomic magnetometers for miniaturization and extreme sensitivity, the proof-of-principle presented in this Letter opens up promising avenues in the development of instrumentation for MIT. PMID:25490470

  11. Magnetic-film atom chip with 10 μm period lattices of microtraps for quantum information science with Rydberg atoms

    SciTech Connect

    Leung, V. Y. F.; Complex Photonic Systems , MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede ; Pijn, D. R. M.; Schlatter, H.; Torralbo-Campo, L.; La Rooij, A. L.; Mulder, G. B.; Naber, J.; Soudijn, M. L.; Tauschinsky, A.; Spreeuw, R. J. C.; Abarbanel, C.; Hadad, B.; Golan, E.; Folman, R.

    2014-05-15

    We describe the fabrication and construction of a setup for creating lattices of magnetic microtraps for ultracold atoms on an atom chip. The lattice is defined by lithographic patterning of a permanent magnetic film. Patterned magnetic-film atom chips enable a large variety of trapping geometries over a wide range of length scales. We demonstrate an atom chip with a lattice constant of 10 μm, suitable for experiments in quantum information science employing the interaction between atoms in highly excited Rydberg energy levels. The active trapping region contains lattice regions with square and hexagonal symmetry, with the two regions joined at an interface. A structure of macroscopic wires, cutout of a silver foil, was mounted under the atom chip in order to load ultracold {sup 87}Rb atoms into the microtraps. We demonstrate loading of atoms into the square and hexagonal lattice sections simultaneously and show resolved imaging of individual lattice sites. Magnetic-film lattices on atom chips provide a versatile platform for experiments with ultracold atoms, in particular for quantum information science and quantum simulation.

  12. Magnetic-field-tunable Kondo effect in alkaline-earth cold atoms

    NASA Astrophysics Data System (ADS)

    Isaev, Leonid; Rey, Ana Maria

    2015-05-01

    We study quantum magnetism in strongly interacting fermionic alkaline-earth atoms (AEAs). Due to the decoupling of electronic and nuclear degrees of freedom, AEAs in two lowest electronic states (1S0 and 3P0) obey an accurate SU(N 2 I + 1) symmetry in their two-body collisions (I is the nuclear spin). We consider a system that realizes the simplest SU(2) case (for atoms prepared in two nuclear-spin states) in an optical lattice with two bands: one localized and one itinerant. For the fully filled narrow band (two atoms per lattice site) we demonstrate that an applied magnetic field provides an efficient control of the local ground state degeneracy due to mixing of spin and orbital two-body states. We derive an effective low-energy model that includes this magnetic-field effect as well as atomic interactions in the two optical lattice bands, and show that it exhibits a peculiar phenomenon of a magnetic field-induced Kondo effect, so far observed only in Coulomb blockaded quantum dots. We expect that our results can be tested with ultracold 173 Yb or 87 Sr atoms. Supported by JILA-NSF-PFC-1125844, NSF-PIF-1211914, ARO, AFOSR, AFOSR-MURI.

  13. An atomic coilgun: using pulsed magnetic fields to slow a supersonic beam

    NASA Astrophysics Data System (ADS)

    Narevicius, E.; Parthey, C. G.; Libson, A.; Narevicius, J.; Chavez, I.; Even, U.; Raizen, M. G.

    2007-10-01

    We report the experimental demonstration of a novel method to slow atoms and molecules with permanent magnetic moments using pulsed magnetic fields. In our experiments, we observe the slowing of a supersonic beam of metastable neon from 461.0 ± 7.7 to 403 ± 16 m s-1 in 18 stages, where the slowed peak is clearly separated from the initial distribution. This method has broad applications as it may easily be generalized, using seeding and entrainment into supersonic beams, to all paramagnetic atoms and molecules.

  14. Microrheology of cells with magnetic force modulation atomic force microscopy.

    PubMed

    Rebêlo, L M; de Sousa, J S; Mendes Filho, J; Schäpe, J; Doschke, H; Radmacher, M

    2014-04-01

    We propose a magnetic force modulation method to measure the stiffness and viscosity of living cells using a modified AFM apparatus. An oscillating magnetic field makes a magnetic cantilever oscillate in contact with the sample, producing a small AC indentation. By comparing the amplitude of the free cantilever motion (A0) with the motion of the cantilever in contact with the sample (A1), we determine the sample stiffness and viscosity. To test the method, the frequency-dependent stiffness of 3T3 fibroblasts was determined as a power law k(s)(f) = α + β(f/f¯)(γ) (α = 7.6 × 10(-4) N m(-1), β = 1.0 × 10(-4) N m(-1), f¯ = 1 Hz, γ = 0.6), where the coefficient γ = 0.6 is in good agreement with rheological data of actin solutions with concentrations similar to those in cells. The method also allows estimation of the internal friction of the cells. In particular we found an average damping coefficient of 75.1 μN s m(-1) for indentation depths ranging between 1.0 μm and 2.0 μm. PMID:24651941

  15. Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases

    NASA Astrophysics Data System (ADS)

    Huang, Xu-Guang

    2016-02-01

    The chiral magnetic and chiral separation effects—quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma—have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects.

  16. Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases.

    PubMed

    Huang, Xu-Guang

    2016-01-01

    The chiral magnetic and chiral separation effects-quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma-have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects. PMID:26868084

  17. Remote energetic neutral atom imaging of electric potential over a lunar magnetic anomaly

    NASA Astrophysics Data System (ADS)

    Futaana, Y.; Barabash, S.; Wieser, M.; Lue, C.; Wurz, P.; Vorburger, A.; Bhardwaj, A.; Asamura, K.

    2013-01-01

    Abstract<p label="1">The formation of electric potential over lunar <span class="hlt">magnetized</span> regions is essential for understanding fundamental lunar science, for understanding the lunar environment, and for planning human exploration on the Moon. A large positive electric potential was predicted and detected from single point measurements. Here, we demonstrate a remote imaging technique of electric potential mapping at the lunar surface, making use of a new concept involving hydrogen neutral <span class="hlt">atoms</span> derived from solar wind. We apply the technique to a lunar <span class="hlt">magnetized</span> region using an existing dataset of the neutral <span class="hlt">atom</span> energy spectrometer SARA/CENA on Chandrayaan-1. Electrostatic potential larger than +135 V inside the Gerasimovic anomaly is confirmed. This structure is found spreading all over the <span class="hlt">magnetized</span> region. The widely spread electric potential can influence the local plasma and dust environment near the <span class="hlt">magnetic</span> anomaly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4751543','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4751543"><span id="translatedtitle">Simulating Chiral <span class="hlt">Magnetic</span> and Separation Effects with Spin-Orbit Coupled <span class="hlt">Atomic</span> Gases</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huang, Xu-Guang</p> <p>2016-01-01</p> <p>The chiral <span class="hlt">magnetic</span> and chiral separation effects—quantum-anomaly-induced electric current and chiral current along an external <span class="hlt">magnetic</span> field in parity-odd quark-gluon plasma—have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external <span class="hlt">magnetic</span> field. These effects can induce a mass quadrupole in the <span class="hlt">atomic</span> cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled <span class="hlt">atomic</span> gases are potential simulators of the chiral <span class="hlt">magnetic</span> and separation effects. PMID:26868084</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21028041','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21028041"><span id="translatedtitle"><span class="hlt">Magnetically</span> controlled velocity selection in a cold-<span class="hlt">atom</span> sample using stimulated Raman transitions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Terraciano, Matthew L.; Olson, Spencer E.; Bashkansky, Mark; Dutton, Zachary; Fatemi, Fredrik K.</p> <p>2007-11-15</p> <p>We observe velocity-selective two-photon resonances in a cold <span class="hlt">atom</span> cloud in the presence of a <span class="hlt">magnetic</span> field. We use these resonances to demonstrate a simple magnetometer with sub-mG resolution. The technique is particularly useful for zeroing the <span class="hlt">magnetic</span> field and does not require any additional laser frequencies than are already used for standard magneto-optical traps. We verify the effects using Faraday rotation spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/385737','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/385737"><span id="translatedtitle"><span class="hlt">Magnetic</span> Dichroism in the Angular Distribution of <span class="hlt">Atomic</span> Oxygen {bold 2}{ital p} Photoelectrons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Plotzke, O.; Pruemper, G.; Zimmermann, B.; Becker, U.; Kleinpoppen, H.</p> <p>1996-09-01</p> <p>A substantial difference in the angular distributions of 2{ital p} photoelectrons from polarized oxygen <span class="hlt">atoms</span> was found for two antiparallel <span class="hlt">atomic</span> polarizations. This <span class="hlt">magnetic</span> dichroism was studied as a function of photon energy from 25 to 52eV. Our method extends traditional photoelectron angular distribution measurements of open shell <span class="hlt">atoms</span> to {open_quote}{open_quote}complete{close_quote}{close_quote} experiments in similar to spin-resolved measurements. The observed dichroism allows a determination of the dipole matrix elements for the {epsilon}{ital s} and {epsilon}{ital d} photoelectrons and their phase difference including the sign. {copyright} {ital 1996 The American Physical Society.}</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/40204668','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/40204668"><span id="translatedtitle">Calculations of <span class="hlt">Magnetic</span> Moments for Three-Electron <span class="hlt">Atomic</span> Systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yan, Zong-Chao</p> <p>2001-06-18</p> <p>The first fully correlated calculations of the <span class="hlt">magnetic</span> moment in lithium are presented. Relative to the free-electron value, the Zeeman g{sub J} factor for the ground state lithium g{sub J}/g{sub e}{minus}1 is calculated to a computational accuracy of 200parts in 10{sup 9} , including relativistic and radiative corrections of orders {alpha}{sup 2} , {alpha}{sup 2}m/M , and {alpha}{sup 3} . The isotope shifts in g{sub J} are predicted precisely for various isotopes. The extensions to the first excited S state of lithium and the ground state of Be{sup +} are made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21016031','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21016031"><span id="translatedtitle">Optical lattice polarization effects on <span class="hlt">magnetically</span> induced optical <span class="hlt">atomic</span> clock transitions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Taichenachev, A. V.; Yudin, V. I.; Oates, C. W.</p> <p>2007-08-15</p> <p>We derive the frequency shift for a forbidden optical transition J=0{yields}J{sup '}=0 caused by the simultaneous actions of an elliptically polarized lattice field and a static <span class="hlt">magnetic</span> field. We find that a simple configuration of lattice and <span class="hlt">magnetic</span> fields leads to a cancellation of this shift to first order in lattice intensity and <span class="hlt">magnetic</span> field. In this geometry, the second-order lattice intensity shift can be minimized as well by use of optimal lattice polarization. Suppression of these shifts could considerably enhance the performance of the next generation of <span class="hlt">atomic</span> clocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChPhB..24b4203W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChPhB..24b4203W"><span id="translatedtitle">Comparison of two absorption imaging methods to detect cold <span class="hlt">atoms</span> in <span class="hlt">magnetic</span> trap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Yan; Hu, Zhao-Hui; Qi, Lu</p> <p>2015-02-01</p> <p>Two methods of absorption imaging to detect cold <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> trap are implemented for a high-precision cold <span class="hlt">atom</span> interferometer. In the first method, a probe laser which is in resonance with a cycle transition frequency is used to evaluate the quantity and distribution of the <span class="hlt">atom</span> sample. In the second method, the probe laser is tuned to an open transition frequency, which stimulates a few and constant number of photons per <span class="hlt">atom</span>. This method has a shorter interaction time and results in absorption images which are not affected by the <span class="hlt">magnetic</span> field and the light field. We make a comparison of performance between these two imaging methods in the sense of parameters such as pulse duration, light intensity, and <span class="hlt">magnetic</span> field strength. The experimental results show that the second method is more reliable when detecting the quantity and density profiles of the <span class="hlt">atoms</span>. These results fit well to the theoretical analysis. Project supported by the National Natural Science Foundation of China (Grant Nos. 61227902 and 61121003) and the National Defense Basic Scientific Research Program of China (Grant No. B2120132005).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3397402','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3397402"><span id="translatedtitle">Single-molecule force spectroscopy: optical tweezers, <span class="hlt">magnetic</span> tweezers and <span class="hlt">atomic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Neuman, Keir C.; Nagy, Attila</p> <p>2012-01-01</p> <p>Single-molecule force spectroscopy has emerged as a powerful tool to investigate the forces and motions associated with biological molecules and enzymatic activity. The most common force spectroscopy techniques are optical tweezers, <span class="hlt">magnetic</span> tweezers and <span class="hlt">atomic</span> force microscopy. These techniques are described and illustrated with examples highlighting current capabilities and limitations. PMID:18511917</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA13C4019P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA13C4019P"><span id="translatedtitle">Sudden Stratospheric <span class="hlt">Warming</span> Effects over L1 Scintillation at Low Latitude During Quiet and <span class="hlt">Magnetically</span> Disturbed Periods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paula, E. R.; Jonah, O. F.; Moraes, A. O.; Kherani, E. A.; Fejer, B. G.; Abdu, M. A.; Batista, I. S.; Negreti, P. M. D. S.; Dutra, S. L. G.; Paes, R. D. R.</p> <p>2014-12-01</p> <p>Small scale irregularities of hundred of meters, associated with bubbles cause scattering and diffraction of radio waves crossing the ionosphere and produces scintillation in amplitude and/or phase of the GNSS signal that can cause loss of lock of its code and/or carrier, affecting the positioning determination. The L1 band GPS amplitude scintillation intensities, represented by the S4 scintillation index, at the low latitude station of São José dos Campos (23.1º S, 45.8º W, dip latitude 17.3º S), located under the southern crest of the EIA, were analyzed during two northern hemisphere Sudden Stratospheric <span class="hlt">Warming</span> (SSW) events. These events occurred during the northern winter months of 2003/2004 marked by moderate <span class="hlt">magnetic</span> disturbances and 2012/2013 during a very quiet <span class="hlt">magnetic</span> period. Normally during these months (January to February) moderate to strong scintillation occurs in this Brazilian station for moderate and high solar flux. Long lasting weakening of the scintillation amplitude at this low latitude station was observed during these two SSW events, compared to the pre-SSW periods, however stronger S4 weakening was observed during 2003/2004. The main mechanisms that can lead to scintillation weakening are the meridional neutral wind and the equatorial vertical plasma drift. Since no wind data is available during pre-SSW and SSW periods, we have sought to identify its signature in the latitudinal distribution of the TEC along the 60o <span class="hlt">magnetic</span> meridian and we suggest that a SSW induced southward meridional wind had a large contribution to the S4 weakening. The other mechanism that could have contributed to S4 weakening is the vertical plasma drift. This parameter, inferred from São Luís (2.52°S, 44.3°W, dip latitude 1.73°S) digisonde data for the 17 to 21 LT period during the SSW events, showed predominant decreases around the prereversal hours relative to their pre-SSW periods. The vertical drift during the period of the 2003/2004 SSW event presented a large flattening and remained constant at about 10 m/s. We suggest that this larger drift decrease during the <span class="hlt">magnetic</span> storm, compared to the 2012/2013 SSW period, is caused by the SSW effects reinforced by the disturbance dynamo and overshielding westward polarity electric fields associated with the storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22072592','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22072592"><span id="translatedtitle">Average <span class="hlt">atom</span> transport properties for pure and mixed species in the hot and <span class="hlt">warm</span> dense matter regimes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Starrett, C. E.; Kress, J. D.; Collins, L. A.; Hanson, D. E.; Clerouin, J.; Recoules, V.</p> <p>2012-10-15</p> <p>The Kubo-Greenwood formulation for calculation of optical conductivities with an average <span class="hlt">atom</span> model is extended to calculate thermal conductivities. The method is applied to species and conditions of interest for inertial confinement fusion. For the mixed species studied, the partial pressure mixing rule is used. Results including pressures, dc, and thermal conductivities are compared to ab initio calculations. Agreement for pressures is good, for both the pure and mixed species. For conductivities, it is found that the ad hoc renormalization method with line broadening, described in the text, gives best agreement with the ab initio results. However, some disagreement is found and the possible reasons for this are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvB..91s5433P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvB..91s5433P"><span id="translatedtitle"><span class="hlt">Atomic</span>-resolution single-spin <span class="hlt">magnetic</span> resonance detection concept based on tunneling force microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Payne, A.; Ambal, K.; Boehme, C.; Williams, C. C.</p> <p>2015-05-01</p> <p>A study of a force detected single-spin <span class="hlt">magnetic</span> resonance measurement concept with <span class="hlt">atomic</span> spatial resolution is presented. The method is based upon electrostatic force detection of spin-selection rule controlled single-electron tunneling between two electrically isolated paramagnetic states. Single-spin <span class="hlt">magnetic</span> resonance detection is possible by measuring the force detected tunneling charge noise on and off spin resonance. Simulation results of this charge noise, based upon physical models of the tunneling and spin physics, are directly compared to measured <span class="hlt">atomic</span> force microscopy system noise. The results show that the approach could provide single-spin measurement of electrically isolated qubit states with <span class="hlt">atomic</span> spatial resolution at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20898638','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20898638"><span id="translatedtitle">Spectroscopic Studies of <span class="hlt">Atomic</span> and Molecular Processes in the Edge Region of <span class="hlt">Magnetically</span> Confined Fusion Plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hey, J. D.; Brezinsek, S.; Mertens, Ph.; Unterberg, B.</p> <p>2006-12-01</p> <p>Edge plasma studies are of vital importance for understanding plasma-wall interactions in <span class="hlt">magnetically</span> confined fusion devices. These interactions determine the transport of neutrals into the plasma, and the properties of the plasma discharge. This presentation deals with optical spectroscopic studies of the plasma boundary, and their role in elucidating the prevailing physical conditions. Recorded spectra are of four types: emission spectra of ions and <span class="hlt">atoms</span>, produced by electron impact excitation and by charge-exchange recombination, <span class="hlt">atomic</span> spectra arising from electron impact-induced molecular dissociation and ionisation, visible spectra of molecular hydrogen and its isotopic combinations, and laser-induced fluorescence (LIF) spectra. The <span class="hlt">atomic</span> spectra are strongly influenced by the confining <span class="hlt">magnetic</span> field (Zeeman and Paschen-Back effects), which produces characteristic features useful for species identification, temperature determination by Doppler broadening, and studies of chemical and physical sputtering. Detailed analysis of the Zeeman components in both optical and LIF spectra shows that <span class="hlt">atomic</span> hydrogen is produced in various velocity classes, some related to the relevant molecular Franck-Condon energies. The latter reflect the dominant electron collision processes responsible for production of <span class="hlt">atoms</span> from molecules. This assignment has been verified by gas-puffing experiments through special test limiters. The higher-energy flanks of hydrogen line profiles probably also show the influence of charge-exchange reactions with molecular ions accelerated in the plasma sheath ('scrape-off layer') separating limiter surfaces from the edge plasma, in analogy to acceleration in the cathode-fall region of gas discharges. While electron collisions play a vital role in generating the spectra, ion collisions with excited <span class="hlt">atomic</span> radiators act through re-distribution of population among the <span class="hlt">atomic</span> fine-structure sublevels, and momentum transfer to the <span class="hlt">atomic</span> nuclei via ion-induced dipole collisions with the bound electrons. The ions are thus important in randomising and equilibrating the velocity distribution of <span class="hlt">atomic</span> products of molecular dissociation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26852801','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26852801"><span id="translatedtitle">Probing of multiple <span class="hlt">magnetic</span> responses in <span class="hlt">magnetic</span> inductors using <span class="hlt">atomic</span> force microscopy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Seongjae; Seo, Hosung; Seol, Daehee; Yoon, Young-Hwan; Kim, Mi Yang; Kim, Yunseok</p> <p>2016-01-01</p> <p>Even though nanoscale analysis of <span class="hlt">magnetic</span> properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various <span class="hlt">magnetic</span> properties associated with eddy current, coil current and <span class="hlt">magnetic</span> domains in <span class="hlt">magnetic</span> inductors using multidimensional <span class="hlt">magnetic</span> force microscopy (MMFM). The MMFM images provide combined <span class="hlt">magnetic</span> responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing <span class="hlt">magnetic</span> responses can be further extended to the analysis of local physical features. PMID:26852801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745108','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4745108"><span id="translatedtitle">Probing of multiple <span class="hlt">magnetic</span> responses in <span class="hlt">magnetic</span> inductors using <span class="hlt">atomic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Park, Seongjae; Seo, Hosung; Seol, Daehee; Yoon, Young-Hwan; Kim, Mi Yang; Kim, Yunseok</p> <p>2016-01-01</p> <p>Even though nanoscale analysis of <span class="hlt">magnetic</span> properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various <span class="hlt">magnetic</span> properties associated with eddy current, coil current and <span class="hlt">magnetic</span> domains in <span class="hlt">magnetic</span> inductors using multidimensional <span class="hlt">magnetic</span> force microscopy (MMFM). The MMFM images provide combined <span class="hlt">magnetic</span> responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing <span class="hlt">magnetic</span> responses can be further extended to the analysis of local physical features. PMID:26852801</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...620794P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...620794P"><span id="translatedtitle">Probing of multiple <span class="hlt">magnetic</span> responses in <span class="hlt">magnetic</span> inductors using <span class="hlt">atomic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Seongjae; Seo, Hosung; Seol, Daehee; Yoon, Young-Hwan; Kim, Mi Yang; Kim, Yunseok</p> <p>2016-02-01</p> <p>Even though nanoscale analysis of <span class="hlt">magnetic</span> properties is of significant interest, probing methods are relatively less developed compared to the significance of the technique, which has multiple potential applications. Here, we demonstrate an approach for probing various <span class="hlt">magnetic</span> properties associated with eddy current, coil current and <span class="hlt">magnetic</span> domains in <span class="hlt">magnetic</span> inductors using multidimensional <span class="hlt">magnetic</span> force microscopy (MMFM). The MMFM images provide combined <span class="hlt">magnetic</span> responses from the three different origins, however, each contribution to the MMFM response can be differentiated through analysis based on the bias dependence of the response. In particular, the bias dependent MMFM images show locally different eddy current behavior with values dependent on the type of materials that comprise the MI. This approach for probing <span class="hlt">magnetic</span> responses can be further extended to the analysis of local physical features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011mast.conf..280S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011mast.conf..280S"><span id="translatedtitle"><span class="hlt">Magnetic</span> Fields of M-Dwarfs from the Molecular and <span class="hlt">Atomic</span> Diagnostics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shulyak, D.; Reiners, A.; Wende, S.; Kochukhov, O.; Piskunov, N.; Seifahrt, A.</p> <p></p> <p>Strong surface <span class="hlt">magnetic</span> fields are frequently found in the spectra of M-dwarfs, with the mean intensities on the order of a few thousand Gauss - three orders of magnitude higher than the mean surface <span class="hlt">magnetic</span> field of the Sun. The appearance of such fields in both partially and fully convective M-dwarfs provides strong constraints on the theoretical models of stellar <span class="hlt">magnetism</span>. The accurate estimates of the <span class="hlt">magnetic</span> field intensity and geometry in these cool objects, however, is strongly limited to our ability to simulate the Zeeman effect in molecular lines. Here we present the first quantitative results of modelling and analysis of the <span class="hlt">magnetic</span> fields in selected M-dwarfs in FeH Wing-Ford F^4Δ-X^4Δ transitions and some strong <span class="hlt">atomic</span> lines from polarised radiative transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAP...119n3901Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAP...119n3901Z"><span id="translatedtitle">Ultra-sensitive <span class="hlt">atomic</span> magnetometer for studying <span class="hlt">magnetization</span> fields produced by hyperpolarized helium-3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zou, Sheng; Zhang, Hong; Chen, Xi-yuan; Chen, Yao; Lu, Ji-xi; Hu, Zhao-hui; Shan, Guang-cun; Quan, Wei; Fang, Jian-cheng</p> <p>2016-04-01</p> <p>An ingenious approach to acquire the absolute <span class="hlt">magnetization</span> fields produced by polarized <span class="hlt">atoms</span> has been presented in this paper. The method was based on detection of spin precession signal of the hyperpolarized helium-3 with ultra-sensitive <span class="hlt">atomic</span> magnetometer of potassium by referring to time-domain analysis. At first, dynamic responses of the mixed spin ensembles in the presence of variant external <span class="hlt">magnetic</span> fields have been analyzed by referring to the Bloch equation. Subsequently, the relevant equipment was established to achieve the functions of hyperpolarizing helium-3 and detecting the precession of spin-polarized noble gas. By analyzing the transient response of the magnetometer in time domain, we obtained the relevant damping ratio and natural frequency. When the value of damping ratio reached the maximum value of 0.0917, the combined <span class="hlt">atomic</span> magnetometer was in equilibrium. We draw a conclusion from the steady response: the <span class="hlt">magnetization</span> fields of the polarized electrons and the hyperpolarized nuclei were corresponding 16.12 nT and 90.74 nT. Under this situation, the nuclear <span class="hlt">magnetization</span> field could offset disturbing <span class="hlt">magnetic</span> fields perpendicular to the orientation of the electronic polarization, and it preserved the electronic spin staying in a stable axis. Therefore, the combined magnetometer was particularly attractive for inertial measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvB..90f4423N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvB..90f4423N"><span id="translatedtitle">Structure and <span class="hlt">magnetism</span> of Tm <span class="hlt">atoms</span> and monolayers on W(110)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nistor, Corneliu; Mugarza, Aitor; Stepanow, Sebastian; Gambardella, Pietro; Kummer, Kurt; Diez-Ferrer, José Luis; Coffey, David; de la Fuente, César; Ciria, Miguel; Arnaudas, José I.</p> <p>2014-08-01</p> <p>We investigated the growth and <span class="hlt">magnetic</span> properties of Tm <span class="hlt">atoms</span> and monolayers deposited on a W(110) surface using scanning tunneling microscopy and x-ray <span class="hlt">magnetic</span> circular and linear dichroism. The equilibrium structure of Tm monolayer films is found to be a strongly distorted hexagonal lattice with a Moiré pattern due to the overlap with the rectangular W(110) substrate. Monolayer as well as isolated Tm adatoms on W present a trivalent ground-state electronic configuration, contrary to divalent gas phase Tm and weakly coordinated <span class="hlt">atoms</span> in quench-condensed Tm films. Ligand field multiplet simulations of the x-ray absorption spectra further show that Tm has a |J=6,Jz=±5> electronic ground state separated by a few meV from the next lowest substates |J=6,Jz=±4> and |J=6,Jz=±6>. Accordingly, both the Tm <span class="hlt">atoms</span> and monolayer films exhibit large spin and orbital moments with out-of-plane uniaxial <span class="hlt">magnetic</span> anisotropy. X-ray <span class="hlt">magnetic</span> dichroism measurements as a function of temperature show that the Tm monolayers develop antiferromagnetic correlations at about 50 K. The triangular structure of the Tm lattice suggests the presence of significant <span class="hlt">magnetic</span> frustration in this system, which may lead to either a noncollinear staggered spin structure or intrinsic disorder.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22410318','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22410318"><span id="translatedtitle">Confinement effects of <span class="hlt">magnetic</span> field on two-dimensional hydrogen <span class="hlt">atom</span> in plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bahar, M. K.; Soylu, A.</p> <p>2015-05-15</p> <p>In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence and in the absence of an external <span class="hlt">magnetic</span> field within two-dimensional formalism using the asymptotic iteration method. The MGECSC potential includes four different potential forms when considering different sets of the parameters in the potential. The plasma screening effects in the weak and strong <span class="hlt">magnetic</span> field regimes as well as the confinement effects of <span class="hlt">magnetic</span> field on the two-dimensional hydrogen <span class="hlt">atom</span> in Debye and quantum plasmas are investigated by solving the corresponding equations. It is found that applying a uniform <span class="hlt">magnetic</span> field on the hydrogen <span class="hlt">atom</span> embedded in a plasma leads to change in the profile of the total interaction potential. Thus, confinement effects of <span class="hlt">magnetic</span> field on hydrogen <span class="hlt">atom</span> embedded in Debye and quantum plasmas modeled by a MGECSC potential lead to shift bound state energies. This effect would be important to isolate the plasma from the external environment in the experimental applications of plasma physics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22402728','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22402728"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn{sub 2}CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jamer, M. E.; Assaf, B. A.; Heiman, D.; Sterbinsky, G. E.; Arena, D. A.</p> <p>2014-12-07</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn{sub 2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1174115-atomic-moments-mn2coal-thin-films-analyzed-ray-magnetic-circular-dichroism','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1174115-atomic-moments-mn2coal-thin-films-analyzed-ray-magnetic-circular-dichroism"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn2CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.</p> <p>2014-12-05</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21544614','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21544614"><span id="translatedtitle"><span class="hlt">Atomic</span> electric dipole moment induced by the nuclear electric dipole moment: The <span class="hlt">magnetic</span> moment effect</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Porsev, S. G.; Ginges, J. S. M.; Flambaum, V. V.</p> <p>2011-04-15</p> <p>We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in <span class="hlt">atoms</span> through the interaction of a nuclear EDM d{sub N} with the hyperfine interaction, the ''<span class="hlt">magnetic</span> moment effect''. We have derived the operator for this interaction and presented analytical formulas for the matrix elements between <span class="hlt">atomic</span> states. Induced EDMs in the diamagnetic <span class="hlt">atoms</span> {sup 129}Xe, {sup 171}Yb, {sup 199}Hg, {sup 211}Rn, and {sup 225}Ra have been calculated numerically. From the experimental limits on the <span class="hlt">atomic</span> EDMs of {sup 129}Xe and {sup 199}Hg we have placed the following constraints on the nuclear EDMs, |d{sub N}({sup 129}Xe)|<1.1x10{sup -21}|e|cm and |d{sub N}({sup 199}Hg)|<2.8x10{sup -24}|e|cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IAUS..303...73G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IAUS..303...73G"><span id="translatedtitle">The <span class="hlt">warm</span> ISM in the Sgr A region: mid-J CO, <span class="hlt">atomic</span> carbon, ionized <span class="hlt">atomic</span> carbon, and ionized nitrogen line observations with the Herschel/HIFI and NANTEN2/SMART Telescopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García, Pablo; Simon, Robert; Stutzki, Jürgen; Requena-Torres, Miguel; Güsten, Rolf; Fukui, Yasuo; Yamamoto, Hiroaki; Bertoldi, Frank; Burton, Michael; Bronfman, Leonardo; Ogawa, Hideo</p> <p>2014-05-01</p> <p>We present Herschel/HIFI sub-mm <span class="hlt">atomic</span> carbon ([Ci] 3 P 1 - 3 P 0 and [Ci] 3 P 2 - 3 P 1), ionized carbon ([Cii] 2 P 3/2 - 2 P 1/2), and ionized nitrogen ([Nii] 3 P 1 - 3 P 0) line observations obtained in the frame of the Herschel Guaranteed Time HEXGAL (Herschel EXtraGALactic) key program (P. I. Rolf Güsten, MPIfR), and NANTEN2/SMART carbon monoxide (CO(J = 4 - 3)) observations of the <span class="hlt">warm</span> gas around the Sgr A region. The spectrally resolved emission from all lines, and the corresponding line intensity ratios, show a very complex morphology. The determination of spatial and spectral (anti)correlation with known sources in the Sgr A region such as the Arched Filaments, NTF filaments, the Sickle, Quintuplet cluster, CND clouds, is ongoing work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22489515','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489515"><span id="translatedtitle">Energetics, diffusion, and <span class="hlt">magnetic</span> properties of cobalt <span class="hlt">atom</span> in a monolayer graphene: An ab initio study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Raji, Abdulrafiu T.; Lombardi, Enrico B.</p> <p>2015-09-21</p> <p>We use ab initio methods to study the binding, diffusion, and <span class="hlt">magnetic</span> properties of cobalt <span class="hlt">atom</span> embedded in graphene vacancies. We investigate the diffusion of Co-monovacancy (Co-MV) and Co-divacancy (Co-DV) defect complexes, and determine the minimum energy path (MEP), as well as the activation energy barrier of migration. We obtained similar activation energy barriers, of ∼5.8 eV, for Co-MV and Co-DV diffusion, respectively. Our calculations also suggest that, at electron–irradiation energy of 200 keV as used in a related experiment, the maximum energy transfer to the Co <span class="hlt">atom</span>, of approximately 9.0 eV is sufficiently high to break metal-carbon bonding. The incident electron energy is also high enough to displace graphene's carbon <span class="hlt">atoms</span> from their lattice positions. The breaking of metal-carbon bonding and the displacement of graphene <span class="hlt">atoms</span> may act to facilitate the migration of Co. We conclude therefore that the detrapping and diffusion of cobalt as observed experimentally is likely to be radiation-induced, similar to what has been observed for Au and Fe in electron-irradiated graphene. Furthermore, we show that Co migration in graphene is such that its <span class="hlt">magnetic</span> moment varies along the diffusion path. The <span class="hlt">magnetic</span> moment of Co is consistently higher in Co-DV diffusion when compared to that of Co-MV diffusion.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...618401Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...618401Z"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26813143','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26813143"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications. PMID:26813143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4728408','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4728408"><span id="translatedtitle">Controlled Phase and Tunable <span class="hlt">Magnetism</span> in Ordered Iron Oxide Nanotube Arrays Prepared by <span class="hlt">Atomic</span> Layer Deposition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Yijun; Liu, Ming; Peng, Bin; Zhou, Ziyao; Chen, Xing; Yang, Shu-Ming; Jiang, Zhuang-De; Zhang, Jie; Ren, Wei; Ye, Zuo-Guang</p> <p>2016-01-01</p> <p>Highly-ordered and conformal iron oxide nanotube arrays on an <span class="hlt">atomic</span> scale are successfully prepared by <span class="hlt">atomic</span> layer deposition (ALD) with controlled oxidization states and tunable <span class="hlt">magnetic</span> properties between superparamagnetism and ferrimagnetism. Non-<span class="hlt">magnetic</span> α-Fe2O3 and superparamagnetic Fe3O4 with a blocking temperature of 120 K are in-situ obtained by finely controlling the oxidation reaction. Both of them exhibit a very small grain size of only several nanometers due to the nature of <span class="hlt">atom-by-atom</span> growth of the ALD technique. Post-annealing α-Fe2O3 in a reducing atmosphere leads to the formation of the spinel Fe3O4 phase which displays a distinct ferrimagnetic anisotropy and the Verwey metal-insulator transition that usually takes place only in single crystal magnetite or thick epitaxial films at low temperatures. The ALD deposition of iron oxide with well-controlled phase and tunable <span class="hlt">magnetism</span> demonstrated in this work provides a promising opportunity for the fabrication of 3D nano-devices to be used in catalysis, spintronics, microelectronics, data storages and bio-applications. PMID:26813143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389787','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3389787"><span id="translatedtitle"><span class="hlt">Magnetic</span> Relaxometry with an <span class="hlt">Atomic</span> Magnetometer and SQUID Sensors on Targeted Cancer Cells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Johnson, Cort; Adolphi, Natalie L.; Butler, Kimberly L.; Debbie M, Lovato; Larson, Richard; Schwindt, Peter D.D.; Flynn, Edward R.</p> <p>2012-01-01</p> <p><span class="hlt">Magnetic</span> relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting Quantum Interference Device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 <span class="hlt">magnetically</span>-labeled cancer cells. The emerging technology of <span class="hlt">atomic</span> magnetometers (AM) represents a new detection method for <span class="hlt">magnetic</span> relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of <span class="hlt">magnetic</span> relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the <span class="hlt">magnetic</span> decay characteristics following a <span class="hlt">magnetization</span> pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and <span class="hlt">magnetic</span> moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting <span class="hlt">magnetically</span> labeled cells does not require cryogenic cooling and is relatively inexpensive. PMID:22773885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22773885','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22773885"><span id="translatedtitle"><span class="hlt">Magnetic</span> Relaxometry with an <span class="hlt">Atomic</span> Magnetometer and SQUID Sensors on Targeted Cancer Cells.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnson, Cort; Adolphi, Natalie L; Butler, Kimberly L; Debbie M, Lovato; Larson, Richard; Schwindt, Peter D D; Flynn, Edward R</p> <p>2012-08-01</p> <p><span class="hlt">Magnetic</span> relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting Quantum Interference Device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 <span class="hlt">magnetically</span>-labeled cancer cells. The emerging technology of <span class="hlt">atomic</span> magnetometers (AM) represents a new detection method for <span class="hlt">magnetic</span> relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of <span class="hlt">magnetic</span> relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the <span class="hlt">magnetic</span> decay characteristics following a <span class="hlt">magnetization</span> pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and <span class="hlt">magnetic</span> moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting <span class="hlt">magnetically</span> labeled cells does not require cryogenic cooling and is relatively inexpensive. PMID:22773885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26273981','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26273981"><span id="translatedtitle"><span class="hlt">Magnetic</span> Properties of Polycrystalline Bismuth Ferrite Thin Films Grown by <span class="hlt">Atomic</span> Layer Deposition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jalkanen, Pasi; Tuboltsev, Vladimir; Marchand, Benoît; Savin, Alexander; Puttaswamy, Manjunath; Vehkamäki, Marko; Mizohata, Kenichiro; Kemell, Marianna; Hatanpää, Timo; Rogozin, Valentin; Räisänen, Jyrki; Ritala, Mikko; Leskelä, Markku</p> <p>2014-12-18</p> <p>The <span class="hlt">atomic</span> layer deposition (ALD) method was applied to grow thin polycrystalline BiFeO3 (BFO) films on Pt/SiO2/Si substrates. The 50 nm thick films were found to exhibit high resistivity, good morphological integrity, and homogeneity achieved by the applied ALD technique. <span class="hlt">Magnetic</span> characterization revealed saturated <span class="hlt">magnetization</span> of 25 emu/cm(3) with temperature-dependent coercivity varying from 5 to 530 Oe within the temperature range from 300 to 2 K. <span class="hlt">Magnetism</span> observed in the films was found to change gradually from ferromagnetic spin ordering to pinned <span class="hlt">magnetic</span> domain interactions mixed with weak spin-glass-like behavior of <span class="hlt">magnetically</span> frustrated antiferromagnetic/ferromagnetic (AFM-FM) spin ordering depending on the temperature and magnitude of the applied <span class="hlt">magnetic</span> field. Antiferromagnetic order of spin cycloids was broken in polycrystalline films by crystal sizes smaller than the cycloid length (∼60 nm). Uncompensated spincycloids and <span class="hlt">magnetic</span> domain walls were found to be the cause of the high <span class="hlt">magnetization</span> of the BFO films. PMID:26273981</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARS30011N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARS30011N"><span id="translatedtitle">Lattice Monte Carlo Simulation Study <span class="hlt">Atomic</span> Structure of Alnico 5-7 Permanent <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming</p> <p>2015-03-01</p> <p>The fluctuations and increases in price and the issues in supply recently of rare earth metals re-heated the sought for non-rare earth permanent <span class="hlt">magnets</span>. Alnico permanent <span class="hlt">magnets</span> have been considered as promising replacements for rare earth-based permanent <span class="hlt">magnets</span> due to the superiors in the <span class="hlt">magnetic</span> performance at high temperature and the abundances of the constituent elements. Using lattice Monte Carlo simulation in combination with cluster expansion method we study the <span class="hlt">atomic</span> structure of alnico 5-7 permanent <span class="hlt">magnets</span>. We observed the phase separation into FeCo-rich and NiAl-rich phases in alnico 5-7 at low temperature, which is consistent with experiment. The phase boundary between these two phases is quite sharp. Both FeCo-rich and NiAl-rich phases are in B2 ordering with Fe and Al sitting on ?-site and Ni and Co sitting on ?-site. The degree of order of NiAl-rich phase is quite higher than that of FeCo-rich phase and it decreases with temperature slower than that of FeCo-rich phase. We also observed a small and increasing with annealing temperature <span class="hlt">magnetic</span> moment in NiAl-rich phase, implying that the <span class="hlt">magnetic</span> properties of alnico 5-7 could be improved by lowering annealing temperature to diminish the <span class="hlt">magnetism</span> in NiAl-rich phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARC13005B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARC13005B"><span id="translatedtitle">Richard L. Greene Dissertation Award in Experimental Condensed Matter or Materials Physics Talk: Towards single <span class="hlt">atom</span> <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baumann, Susanne</p> <p></p> <p><span class="hlt">Magnetic</span> anisotropy is a fundamental property of <span class="hlt">magnetic</span> materials that governs the stability and directionality of their <span class="hlt">magnetization</span>. At the <span class="hlt">atomic</span> level, <span class="hlt">magnetic</span> anisotropy originates from anisotropy in the orbital angular momentum (L) and the spin-orbit coupling that connects the spin moment of a <span class="hlt">magnetic</span> <span class="hlt">atom</span> to the spatial symmetry of its ligand field environment. Generally, the ligand field, that is necessary for the anisotropy, also quenches the orbital moment and reduces the total <span class="hlt">magnetic</span> moment of the <span class="hlt">atom</span> to its spin component. However, careful design of the coordination geometry of a single <span class="hlt">atom</span> can restore the orbital moment while inducing uniaxial anisotropy, as we present here for single <span class="hlt">atoms</span> deposited on top of a thin MgO film. Scanning tunneling spectroscopy and x-ray absorption spectroscopy measurements show a large <span class="hlt">magnetic</span> anisotropy of 19 meV for iron and 58 meV for cobalt, as well as relaxation times of many milliseconds. These results offer a strategy, based on symmetry arguments and careful tailoring of the interaction with the environment, for the rational design of nanoscopic permanent <span class="hlt">magnets</span> and single <span class="hlt">atom</span> <span class="hlt">magnets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24201042','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24201042"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and <span class="hlt">atomic</span> order effect on the martensitic transformation of a metamagnetic alloy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barandiaran, J M; Chernenko, V A; Cesari, E; Salas, D; Gutierrez, J; Lazpita, P</p> <p>2013-12-01</p> <p>The martensitic transformation (MT) of metamagnetic shape memory alloys is very sensitive to the applied <span class="hlt">magnetic</span> field and <span class="hlt">atomic</span> order. We analyze the alloy Ni50Mn34.5In15.5 in <span class="hlt">magnetic</span> fields up to 13 T. The alloy has been prepared both in an ordered state by slow cooling, and in a disordered state by rapid quenching. In both cases the dependence of the martensitic transition temperature on the field is highly nonlinear. Such departure from linearity is due to a decrease of the entropy change at the transition, ΔS, with the applied field. This can be explained by the ordering effect of the <span class="hlt">magnetic</span> field on the frustrated <span class="hlt">magnetic</span> structure of the alloy in the martensitic phase. Compliance with a recent model, relying on the strong magnetoelastic interactions in these compounds, is very satisfactory. PMID:24201042</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1234461','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1234461"><span id="translatedtitle">New alnico <span class="hlt">magnets</span> fabricated from pre-alloyed gas-<span class="hlt">atomized</span> powder through diverse consolidation techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.</p> <p>2015-05-25</p> <p>Fine Alnico 8 spherical powder produced by gas <span class="hlt">atomization</span> was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and <span class="hlt">magnetic</span> properties were analyzed and compared. The HP, HIP, and CMS <span class="hlt">magnets</span> exhibited different features in microstructures and <span class="hlt">magnetic</span> properties. <span class="hlt">Magnetically</span> annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (H<sub>cj</sub> =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. As a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1234461-new-alnico-magnets-fabricated-from-pre-alloyed-gas-atomized-powder-through-diverse-consolidation-techniques','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1234461-new-alnico-magnets-fabricated-from-pre-alloyed-gas-atomized-powder-through-diverse-consolidation-techniques"><span id="translatedtitle">New alnico <span class="hlt">magnets</span> fabricated from pre-alloyed gas-<span class="hlt">atomized</span> powder through diverse consolidation techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.</p> <p>2015-05-25</p> <p>Fine Alnico 8 spherical powder produced by gas <span class="hlt">atomization</span> was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and <span class="hlt">magnetic</span> properties were analyzed and compared. The HP, HIP, and CMS <span class="hlt">magnets</span> exhibited different features in microstructures and <span class="hlt">magnetic</span> properties. <span class="hlt">Magnetically</span> annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. Asmore » a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1087049','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1087049"><span id="translatedtitle">Giant <span class="hlt">atomic</span> displacement at a <span class="hlt">magnetic</span> phase transition in metastable Mn3O4</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hirai, Shigeto; Moreira Dos Santos, Antonio F; Shapiro, Max C; Molaison, Jamie J; Pradhan, Neelam; Guthrie, Malcolm; Tulk, Christopher A; Fisher, Ian R; Mao, Wendy</p> <p>2013-01-01</p> <p>We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order <span class="hlt">magnetic</span> and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a <span class="hlt">magnetic</span> structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a <span class="hlt">magnetic</span> propagation vector k = [1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the <span class="hlt">magnetic</span> phase transition at 210 K, structural refinements reveal a large <span class="hlt">atomic</span> shift at this phase transition, corresponding to a physical motion of approximately 0.25 angstrom, even though the crystal symmetry remains unchanged. This "giant" response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23964134','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23964134"><span id="translatedtitle"><span class="hlt">Magnetic</span>-resonance imaging of the human brain with an <span class="hlt">atomic</span> magnetometer.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Savukov, I; Karaulanov, T</p> <p>2013-07-22</p> <p><span class="hlt">Magnetic</span> resonance imaging (MRI) is conventionally performed in very high fields, and this leads to some restrictions in applications. To remove such restrictions, the ultra-low field MRI approach has been proposed. Because of the loss of sensitivity, the detection methods based on superconducting quantum interference devices (SQUIDs) in a shielded room were used. <span class="hlt">Atomic</span> magnetometers have similar sensitivity as SQUIDs and can also be used for MRI, but there are some technical difficulties to overcome. We demonstrate that MRI of the human brain can be obtained with an <span class="hlt">atomic</span> magnetometer with in-plane resolution of 3 mm in 13 min. PMID:23964134</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.103d3703S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.103d3703S"><span id="translatedtitle"><span class="hlt">Magnetic</span>-resonance imaging of the human brain with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savukov, I.; Karaulanov, T.</p> <p>2013-07-01</p> <p><span class="hlt">Magnetic</span> resonance imaging (MRI) is conventionally performed in very high fields, and this leads to some restrictions in applications. To remove such restrictions, the ultra-low field MRI approach has been proposed. Because of the loss of sensitivity, the detection methods based on superconducting quantum interference devices (SQUIDs) in a shielded room were used. <span class="hlt">Atomic</span> magnetometers have similar sensitivity as SQUIDs and can also be used for MRI, but there are some technical difficulties to overcome. We demonstrate that MRI of the human brain can be obtained with an <span class="hlt">atomic</span> magnetometer with in-plane resolution of 3 mm in 13 min.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPJD...67..248S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPJD...67..248S"><span id="translatedtitle">Regular and chaotic dynamics of a neutral <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> trap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salas, Jose Pablo; Iñarrea, Manuel</p> <p>2013-12-01</p> <p>In the framework of the nonlinear mechanics, we study the dynamics of a neutral <span class="hlt">atom</span> confined in a <span class="hlt">magnetic</span> quadrupolar trap. Owing to the axial symmetry of the system, the z-component of the angular momentum p φ is an integral of motion and, in cylindrical coordinates, the dynamics of the <span class="hlt">atom</span> is modeled by a two-degree of freedom Hamiltonian. The structure and evolution of the phase space as a function of the energy is explored extensively by means of numerical techniques of continuation of families of periodic orbits and Poincaré surfaces of section.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3739803','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3739803"><span id="translatedtitle"><span class="hlt">Magnetic</span>-resonance imaging of the human brain with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Savukov, I.; Karaulanov, T.</p> <p>2013-01-01</p> <p><span class="hlt">Magnetic</span> resonance imaging (MRI) is conventionally performed in very high fields, and this leads to some restrictions in applications. To remove such restrictions, the ultra-low field MRI approach has been proposed. Because of the loss of sensitivity, the detection methods based on superconducting quantum interference devices (SQUIDs) in a shielded room were used. <span class="hlt">Atomic</span> magnetometers have similar sensitivity as SQUIDs and can also be used for MRI, but there are some technical difficulties to overcome. We demonstrate that MRI of the human brain can be obtained with an <span class="hlt">atomic</span> magnetometer with in-plane resolution of 3 mm in 13 min. PMID:23964134</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93a4410D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93a4410D"><span id="translatedtitle"><span class="hlt">Magnetically</span> driven anisotropic structural changes in the <span class="hlt">atomic</span> laminate M n2GaC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dahlqvist, M.; Ingason, A. S.; Alling, B.; Magnus, F.; Thore, A.; Petruhins, A.; Mockute, A.; Arnalds, U. B.; Sahlberg, M.; Hjörvarsson, B.; Abrikosov, I. A.; Rosen, J.</p> <p>2016-01-01</p> <p>Inherently layered <span class="hlt">magnetic</span> materials, such as <span class="hlt">magnetic</span> Mn +1A Xn (MAX) phases, offer an intriguing perspective for use in spintronics applications and as ideal model systems for fundamental studies of complex <span class="hlt">magnetic</span> phenomena. The MAX phase composition Mn+1A Xn consists of Mn +1Xn blocks separated by <span class="hlt">atomically</span> thin A -layers where M is a transition metal, A an A-group element, X refers to carbon and/or nitrogen, and n is typically 1, 2, or 3. Here, we show that the recently discovered <span class="hlt">magnetic</span> M n2GaC MAX phase displays structural changes linked to the <span class="hlt">magnetic</span> anisotropy, and a rich <span class="hlt">magnetic</span> phase diagram which can be manipulated through temperature and <span class="hlt">magnetic</span> field. Using first-principles calculations and Monte Carlo simulations, an essentially one-dimensional (1D) interlayer plethora of two-dimensioanl (2D) Mn-C-Mn trilayers with robust intralayer ferromagnetic spin coupling was revealed. The complex transitions between them were observed to induce <span class="hlt">magnetically</span> driven anisotropic structural changes. The <span class="hlt">magnetic</span> behavior as well as structural changes dependent on the temperature and applied <span class="hlt">magnetic</span> field are explained by the large number of low energy, i.e., close to degenerate, collinear and noncollinear spin configurations that become accessible to the system with a change in volume. These results indicate that the <span class="hlt">magnetic</span> state can be directly controlled by an applied pressure or through the introduction of stress and show promise for the use of M n2GaC MAX phases in future magnetoelectric and magnetocaloric applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhLA..380.1193H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhLA..380.1193H"><span id="translatedtitle">Characteristics of the resonant instability of surface electrostatic-ion-cyclotron waves in a semi-bounded <span class="hlt">warm</span> <span class="hlt">magnetized</span> dusty plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, Woo-Pyo; Jung, Young-Dae</p> <p>2016-03-01</p> <p>The influence of <span class="hlt">magnetic</span> field and dust rotation on the resonant instability of surface electrostatic-ion-cyclotron wave is kinetically investigated in a semi-bounded <span class="hlt">warm</span> <span class="hlt">magnetized</span> dusty plasma. The dispersion relation and the temporal growth rate of the surface electrostatic-ion-cyclotron wave are derived by the specular-reflection boundary condition including the <span class="hlt">magnetic</span> field and dust rotation effects. It is found that the instability domain decreases with an increase of the rotation frequency of elongated dust grain. It is also found that the dependence of the propagation wave number on the temporal growth rate is more significant for small ion cyclotron frequencies. In addition, it is shown that the scaled growth rate increases with an increase of the strength of <span class="hlt">magnetic</span> field. The variation of the domain and magnitude of temporal growth rate due to the change of plasma parameters is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1157610','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1157610"><span id="translatedtitle">Structural and <span class="hlt">Magnetic</span> Evolution of Bimetallic MnAu Clusters Driven by Asymmetric <span class="hlt">Atomic</span> Migration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wei, Xiaohui; Zhou, Rulong; Lefebvre, Williams; He, Kai; Le Roy, Damien; Skomski, Ralph; Li, Xingzhong; Shield, Jeffrey E; Kramer, Matthew J; Chen, Shuang; Zeng, Xiao Cheng; Sellmyer, David J</p> <p>2014-03-12</p> <p>The nanoscale structural, compositional, and <span class="hlt">magnetic</span> properties are examined for annealed MnAu nanoclusters. The MnAu clusters order into the L10 structure, and monotonic size-dependences develop for the composition and lattice parameters, which are well reproduced by our density functional theory calculations. Simultaneously, Mn diffusion forms 5 Å nanoshells on larger clusters inducing significant <span class="hlt">magnetization</span> in an otherwise antiferromagnetic system. The differing <span class="hlt">atomic</span> mobilities yield new cluster nanostructures that can be employed generally to create novel physical properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069852','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069852"><span id="translatedtitle">Using coherent population trapping in test <span class="hlt">atoms</span> for <span class="hlt">magnetic</span> field measurements in toroidal plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akhmedzhanov, R. A.; Gushchin, L. A.; Zelensky, I. V.; Litvak, A. G.; Tokman, M. D.</p> <p>2007-09-15</p> <p>A way to measure the profile of the safety factor in toroidal controlled-fusion setups has been developed. The method is based on measuring the ratio of the poloidal <span class="hlt">magnetic</span> field and the toroidal one locally, based on a modification of the optical resonance-fluorescence signal. The effect of partial suppression of resonance fluorescence is used, which depends on the orientation of the <span class="hlt">magnetic</span> field relative to the laser beam, and takes place in case of coherent population trapping in test <span class="hlt">atoms</span> with the Zeeman split-level structure, as affected by double-frequency laser radiation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20640449','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20640449"><span id="translatedtitle">Experimentally attainable example of chaotic tunneling: The hydrogen <span class="hlt">atom</span> in parallel static electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Delande, Dominique; Zakrzewski, Jakub</p> <p>2003-12-01</p> <p>Statistics of tunneling rates in the presence of chaotic classical dynamics is discussed on a realistic example: a hydrogen <span class="hlt">atom</span> placed in parallel, uniform, static electric, and <span class="hlt">magnetic</span> fields, where tunneling is followed by ionization along the fields direction. Depending on the <span class="hlt">magnetic</span> quantum number, one may observe either a standard Porter-Thomas distribution of tunneling rates or, for strong scarring by a periodic orbit parallel to the external fields, strong deviations from it. For the latter case, a simple model based on random matrix theory gives the correct distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23171130','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23171130"><span id="translatedtitle">Microwave absorption properties of carbon nanocoils coated with highly controlled <span class="hlt">magnetic</span> materials by <span class="hlt">atomic</span> layer deposition.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Guizhen; Gao, Zhe; Tang, Shiwei; Chen, Chaoqiu; Duan, Feifei; Zhao, Shichao; Lin, Shiwei; Feng, Yuhong; Zhou, Lei; Qin, Yong</p> <p>2012-12-21</p> <p>In this work, <span class="hlt">atomic</span> layer deposition is applied to coat carbon nanocoils with <span class="hlt">magnetic</span> Fe(3)O(4) or Ni. The coatings have a uniform and highly controlled thickness. The coated nanocoils with coaxial multilayer nanostructures exhibit remarkably improved microwave absorption properties compared to the pristine carbon nanocoils. The enhanced absorption ability arises from the efficient complementarity between complex permittivity and permeability, chiral morphology, and multilayer structure of the products. This method can be extended to exploit other composite materials benefiting from its convenient control of the impedance matching and combination of dielectric-<span class="hlt">magnetic</span> multiple loss mechanisms for microwave absorption applications. PMID:23171130</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7256663','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7256663"><span id="translatedtitle">Status of the BNL cold <span class="hlt">atomic</span> beam and its focusing <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hershcovitch, A.; Kponou, A.; DeVito, B.</p> <p>1990-01-01</p> <p>Since the last workshop in Montana, Switzerland, output of the BNL cold <span class="hlt">atomic</span> beam has improved by more than an order of magnitude to a flux of over 10{sup 20} H{sup 0}/sr/s. Spin selection and focusing by three different <span class="hlt">magnets</span>: a superconducting solenoid lens, a long permanent <span class="hlt">magnet</span> sextupole, and a system consisting of two short permanent and electromagnet sextupoles, have been tried. Results indicate that the latter scheme is best for our particular needs. 6 refs., 1 fig., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJP..131...67F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJP..131...67F"><span id="translatedtitle">Rotating effects on an <span class="hlt">atom</span> with a <span class="hlt">magnetic</span> quadrupole moment confined to a quantum ring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fonseca, I. C.; Bakke, Knut</p> <p>2016-03-01</p> <p>We investigate rotating effects on an <span class="hlt">atom</span> with a <span class="hlt">magnetic</span> quadrupole moment that interacts with a radial electric field in a two-dimensional quantum ring through a single-particle approximation (V.F. Dmitriev et al., Phys. Rev. C 50, 2358 (1994)). We show that a Coulomb-type and a linear-type scalar potentials stem from the interaction between <span class="hlt">magnetic</span> quadrupole moment and a radial electric field under rotating effects. Besides, we discuss the dependence of the angular frequency on the angular velocity of the rotating frame and the quantum numbers of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..494..261G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..494..261G"><span id="translatedtitle">Rydberg States of <span class="hlt">Atoms</span> and Molecules in the Atmospheres of Very Cool Stars with <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gnedin, Yu. N.; Piotrovich, M. Yu.; Klyucharev, A. N.</p> <p>2015-04-01</p> <p>We present the results of observations of ultra cool active stars, including new discoveries and determination of spectral types from the SDSS and 2MASS photometric colors. A number of cool dwarfs emit circularly polarized radio waves generated by the electron cyclotron maser instability. Strong infrared absorption is observed in these stars. Model atmosphere calculations indicate that the pure hydrogen composition may be ruled out. The fundamental dipole-dipole interaction between the cold Rydberg <span class="hlt">atoms</span> is the dominant physical process in these stars. The Rydberg states exhibit unique phenomena, such as the spin polarization patterns and giant electric dipole moments induced by the <span class="hlt">magnetic</span> field. As a result, highly excited <span class="hlt">atoms</span> very sensitive to the electric and <span class="hlt">magnetic</span> fields can be used for the spectroscopic detection and compensation for the effects of these fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/467341','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/467341"><span id="translatedtitle">Hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field: Ghost orbits, catastrophes, and uniform semiclassical approximations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Main, J.; Wunner, G.</p> <p>1997-03-01</p> <p>Applying closed-orbit theory to the recurrence spectra of the hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field, one can interpret most, but not all, structures semiclassically in terms of closed classical orbits. In particular, conventional closed-orbit theory fails near bifurcations of orbits where semiclassical amplitudes exhibit unphysical divergences. Here we analyze the role of ghost orbits living in complex phase space. The ghosts can explain resonance structures in the spectra of the hydrogen <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> field at positions where no real orbits exist. For three different types of catastrophes, viz. fold, cusp, and butterfly catastrophes, we construct uniform semiclassical approximations and demonstrate that these solutions are completely determined by classical parameters of the real orbits and complex ghosts. {copyright} {ital 1997} {ital The American Physical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1213313-achieving-atomic-resolution-magnetic-dichroism-controlling-phase-symmetry-electron-probe','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1213313-achieving-atomic-resolution-magnetic-dichroism-controlling-phase-symmetry-electron-probe"><span id="translatedtitle">Achieving <span class="hlt">atomic</span> resolution <span class="hlt">magnetic</span> dichroism by controlling the phase symmetry of an electron probe</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath</p> <p>2014-09-30</p> <p>The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron <span class="hlt">magnetic</span> circular dichroism (EMCD) with <span class="hlt">atomic</span> resolution. It is possible to obtain an EMCD signal with <span class="hlt">atomic</span> resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of a scanning transmission electron microscope. The probe’s required phase distribution depends on the sample’s <span class="hlt">magnetic</span> symmetry and crystal structure. The calculations indicate that EMCD signals that use the electron probe’s phase are as strongmore » as those obtained by nanodiffraction methods.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26322964','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26322964"><span id="translatedtitle">Partial nitrogen <span class="hlt">atom</span> transfer: a new synthetic tool to design single-molecule <span class="hlt">magnets</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Mei; Rouzières, Mathieu; Losovyj, Yaroslav; Pink, Maren; Clérac, Rodolphe; Smith, Jeremy M</p> <p>2015-09-21</p> <p>Incomplete nitrogen <span class="hlt">atom</span> transfer from the iron(IV) nitride complex PhB(MesIm)3Fe≡N to the vanadium(III) complex V(Mes)3(THF) quantitatively provides the bimetallic complex PhB(MesIm)3Fe-N═V(Mes)3. Structural and spectroscopic characterizations reveal that the nitride ligand forms a linear bridge between V(V) and high-spin Fe(II) metal ions, confirming that <span class="hlt">atom</span> transfer is accompanied by electron transfer. In the presence of an applied dc field, the complex displays slow relaxation of the <span class="hlt">magnetization</span>, revealing its single-molecule <span class="hlt">magnet</span> properties with an estimation of the energy barrier at about 10 K. This complex establishes a synthetic principle for the assembly of paramagnetic complexes bridged by nitride ligands. PMID:26322964</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1213313','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1213313"><span id="translatedtitle">Achieving <span class="hlt">atomic</span> resolution <span class="hlt">magnetic</span> dichroism by controlling the phase symmetry of an electron probe</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath</p> <p>2014-09-30</p> <p>The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron <span class="hlt">magnetic</span> circular dichroism (EMCD) with <span class="hlt">atomic</span> resolution. It is possible to obtain an EMCD signal with <span class="hlt">atomic</span> resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of a scanning transmission electron microscope. The probe’s required phase distribution depends on the sample’s <span class="hlt">magnetic</span> symmetry and crystal structure. The calculations indicate that EMCD signals that use the electron probe’s phase are as strong as those obtained by nanodiffraction methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhRvA..60.1975J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhRvA..60.1975J"><span id="translatedtitle">Angular distribution and polarization of <span class="hlt">atomic</span> radiative emission in electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobs, V. L.; Filuk, A. B.</p> <p>1999-09-01</p> <p>A density-matrix approach has been developed for the angular distribution and polarization of radiative emission during single-photon <span class="hlt">atomic</span> transitions for a general set of steady-state excitation processes in an arbitrary arrangement of static (or quasistatic) electric and <span class="hlt">magnetic</span> fields. Particular attention has been directed at spectroscopic observations in the intense fields of the high-power ion diodes on the Particle Beam Fusion Accelerator II (PBFA II) and SABRE devices at Sandia National Laboratories and at <span class="hlt">magnetic</span>-field measurements in tokamak plasmas. The field-dependent <span class="hlt">atomic</span> eigenstates are represented as expansions in a complete basis set of field-free bound and continuum eigenstates. Particular emphasis has been given to directed-electron collisional excitations, which may be produced by an anisotropic incident-electron velocity distribution. We have allowed for the possibility of the coherent excitation of the nearly degenerate field-dependent <span class="hlt">atomic</span> substates, which can give rise to a complex spectral pattern of overlapping Stark-Zeeman components. Coherent excitations may be produced by a beam of electrons that are spin-polarized at an angle with respect to the propagation direction or by nonparallel electric and <span class="hlt">magnetic</span> fields. Our main result is a general expression for the matrix elements of the photon-polarization density operator representing the total intensity, angular distribution, and polarization of the <span class="hlt">atomic</span> radiative emission. For the observation of radiative emission in the direction of the <span class="hlt">magnetic</span> field, the detection of linearly polarized emission, in addition to the usual circularly polarized radiation, can reveal the presence of a perpendicular electric field or a coherent excitation mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21137965','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21137965"><span id="translatedtitle">The migration behavior of <span class="hlt">atomic</span> clusters in early nanocrystalline process of soft <span class="hlt">magnetic</span> Finemet alloy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yuxin; Li, Xiang; Zhang, Yu; Zhao, Guannan; Yan, Biao; Lu, Wei</p> <p>2010-11-01</p> <p>The Finemet alloys are commonly used as cores in transformers and generators, stress and field sensors in technological application for their excellent soft <span class="hlt">magnetic</span> characteristics. To clarify the nanocrystallization mechanism of Finemet especially about the <span class="hlt">atomic</span> migration in early stage is very essential for developing their distinctive characteristics. In this study, we investigate the migration behavior of <span class="hlt">atoms</span> in order to clarify the mechanism of the early-stage nanocrystallization in amorphous Finemet alloys. The Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous ribbons were prepared by single-roller melt-spinning process in argon atmosphere, and then annealed at 350 degrees C-400 degrees C for 10 minutes in vacuum. The <span class="hlt">atom</span> force microscope (AFM) and the coincidence Doppler broadening spectra (CDB) were used to characterize the migration behavior of different <span class="hlt">atoms</span> in Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous alloy during the early-stage nanocrystallization. The X-ray diffraction (XRD) patterns show that all annealed samples are in the amorphous state. But the AFM observation shows clearly that there are many small <span class="hlt">atomic</span> clusters (nuclei) which distribute in the amorphous matrix of the annealed samples. With increasing annealing temperature, there is a significant increase in the amount of <span class="hlt">atomic</span> clusters and a dramatic drop in the average size of clusters with very limited Cu contention in the samples, which reflect the structural evolution into more homogeneity. The CDB spectrum indicates that the peaks of positron annihilation spectrum are gradually reduced, which means the number of grain boundary and the defects in samples are gradually increased. It can be concluded that more defects are introduced by the formation of <span class="hlt">atomic</span> clusters through <span class="hlt">atomic</span> migration during the early-stage nanocrystallization in Fe(73.5)Si(13.5)B9Nb3Cu1 amorphous alloys. PMID:21137965</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9652E..09M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9652E..09M"><span id="translatedtitle"><span class="hlt">Magnetic</span> induction imaging with optical <span class="hlt">atomic</span> magnetometers: towards applications to screening and surveillance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marmugi, Luca; Hussain, Sarah; Deans, Cameron; Renzoni, Ferruccio</p> <p>2015-10-01</p> <p>We propose a new approach, based on optical <span class="hlt">atomic</span> magnetometers and <span class="hlt">magnetic</span> induction tomography (MIT), for remote and non-invasive detection of conductive targets. <span class="hlt">Atomic</span> magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, <span class="hlt">atomic</span> magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating <span class="hlt">magnetic</span> field induces eddy currents in a conductive target and laser-pumped <span class="hlt">atomic</span> magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Global+AND+warming+AND+pollution&pg=3&id=EJ391198','ERIC'); return false;" href="http://eric.ed.gov/?q=Global+AND+warming+AND+pollution&pg=3&id=EJ391198"><span id="translatedtitle">Global <span class="hlt">Warming</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hileman, Bette</p> <p>1989-01-01</p> <p>States the foundations of the theory of global <span class="hlt">warming</span>. Describes methodologies used to measure the changes in the atmosphere. Discusses steps currently being taken in the United States and the world to slow the <span class="hlt">warming</span> trend. Recognizes many sources for the <span class="hlt">warming</span> and the possible effects on the earth. (MVL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1647K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1647K"><span id="translatedtitle"><span class="hlt">Atomic</span> scale study of <span class="hlt">magnetic</span> phase transitions in (Co,Ti;Sc) substituted nanosize barium hexaferrite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krezhov, Kiril</p> <p></p> <p>BaFe12O19 and related isostructural (M-type) hexaferrites derived by single or double cation substitution for Fe3+ with preservation of the formal valence are a recognized group of oxides for their remarkable properties. The <span class="hlt">magnetic</span> interactions may be tuned by suitable substitutions resulting in notable <span class="hlt">magnetic</span> properties utilized extensively for permanent <span class="hlt">magnets</span>, microwave devices and perpendicular recording media. We report on the <span class="hlt">magnetic</span> structure evolution accompanying the <span class="hlt">magnetic</span> anisotropy change, from a combined <span class="hlt">magnetic</span> (SQUID), x-ray and neutron diffraction, and <span class="hlt">magnetic</span> field dependent 57Fe Mössbauer study on BaFe12O19 at selected cation substitutions. The short and long range <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> order in powder samples of nanosize particles prepared by soft chemistry routes were studied and compared with own and literature data for the parent BaFe12O19 compound prepared by solid state reaction. Refinements based on diffraction data show that the <span class="hlt">magnetic</span> structures of BaFe12-xXxO19 (X=Co,Ti; Sc) hexaferrites are largely temperature and substitution dependent. Between 200 and 300K the (Co,Ti)-hexaferrites (x=0.4, 0.7, 0.8, 0.85) display ferrimagnetic structures where the canting of the <span class="hlt">magnetic</span> moments depends on the substitution rate. When lowering the temperature the <span class="hlt">magnetic</span> structure for x=0.45 remains ferrimagnetic down to 10 K, while for x=0.7 and x=0.8 a complex conical <span class="hlt">magnetic</span> structures is finally established. For x=0.85 significant distortions in the local oxygen surrounding of ferric cation sites were established, while the grain-size effect on the structural parameters was considerably smaller. The thermal expansion coefficient exhibits a strong anisotropy. The refined <span class="hlt">magnetic</span> moments are considerably lower than the theoretical spin only moments, especially for the 4e and 12k sites, indicating a local noncollinearity with short-range ordering. The five-cation sublattice collinear ferrimagnetic structure of uniaxial type known as Gorter type for BaFe12O19 remains effective also for BaFe10.4Sc1.6O19 at room temperature and below it down to about 190 K. Below 190 K it gradually transforms into a complex canted structure with spins pointing out of the axial direction so that at 10 K the complex arrangement of <span class="hlt">magnetic</span> moments could be described in terms of an incommensurate complex block-type conical structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93f4407K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93f4407K"><span id="translatedtitle">High-frequency <span class="hlt">magnetization</span> dynamics of individual <span class="hlt">atomic</span>-scale <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krause, S.; Sonntag, A.; Hermenau, J.; Friedlein, J.; Wiesendanger, R.</p> <p>2016-02-01</p> <p>The <span class="hlt">magnetization</span> dynamics of individual nanomagnets is studied by spin-polarized scanning tunneling microscopy, combining real-time telegraphic noise analysis with pump-probe schemes. A transition between two Arrhenius regimes is observed as a function of temperature. The switching rates at high temperature are found to be orders of magnitude lower than expected from the extrapolation from the low-temperature regime. A four-state hopping model of <span class="hlt">magnetization</span> reversal is developed to interpret the experimental results in terms of nucleation, annihilation, and propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.457...74S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.457...74S"><span id="translatedtitle">Time-dependent <span class="hlt">atomic</span> diffusion in <span class="hlt">magnetic</span> ApBp stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stift, M. J.; Alecian, G.</p> <p>2016-03-01</p> <p>Numerical modelling of surface abundance distributions in ApBp star atmospheres constitutes a challenging astrophysical problem. This paper is intended to deepen our understanding of how <span class="hlt">atomic</span> diffusion affects the atmospheric structure of <span class="hlt">magnetic</span> ApBp stars, and in particular how time-dependent calculations may be compared to the alternative method of estimating equilibrium stratifications. Our numerical calculations - with the stellar atmosphere adjusted self-consistently to the abundance profiles - show that final stationary solutions of the time-dependent diffusion problem (constant particle flux throughout the stellar atmosphere) are seemingly at variance with equilibrium stratifications (zero particle flux). In this work, we will provide some understanding of the origin of these differences and try to elucidate the as yet little explored behaviour of time-dependent <span class="hlt">atomic</span> diffusion. To this purpose, we assess the influence of the boundary condition at the bottom of the atmosphere, we investigate how the stratifications depend on <span class="hlt">magnetic</span> field angle and strength, and we have a look at possible interactions between different chemical elements. Based on a grid of atmospheric models and stratifications reflecting dipolar <span class="hlt">magnetic</span> geometries, we also present predicted line profiles for different oblique rotator models. Finally, we shortly discuss the consequences of our findings for the interpretation of abundance maps of <span class="hlt">magnetic</span> ApBp stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/959702','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/959702"><span id="translatedtitle"><span class="hlt">Magnetic</span> and <span class="hlt">Atomic</span> Structure Parameters of Sc-doped Barium Hexagonal Ferrites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang,A.; Chen, Y.; Chen, Z.; Vittoria, C.; Harris, V.</p> <p>2008-01-01</p> <p>Scandium-doped M-type barium hexagonal ferrites of the composition BaFe12?xScxO19 are well suited for low frequency microwave device applications such as isolators and circulators. A series of Sc-doped M-type barium hexagonal ferrite powders (x = 0-1.2) were prepared by conventional ceramic processing techniques. The resulting powders were verified to be pure phase and maintain the nominal chemical stoichiometry by x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Static <span class="hlt">magnetic</span> measurements indicated that both saturation <span class="hlt">magnetization</span> and uniaxial magnetocrystalline anisotropy field decreased with increasing concentration of scandium. Extended x-ray absorption fine structure measurements were carried out to clarify the correlation between the <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> structure properties. It is found that the substituted Sc has a strong preference for the bipyramidal site. Nevertheless, the substitution did not introduce additional <span class="hlt">atomic</span> structural disorder into the barium hexagonal structure. The structural study provided important evidence to quantitatively explain the change in dc and microwave <span class="hlt">magnetic</span> properties due to Sc ion doping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20646381','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20646381"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field-induced quadrupole coupling in the nuclear <span class="hlt">magnetic</span> resonance of noble-gas <span class="hlt">atoms</span> and molecules</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manninen, Pekka; Vaara, Juha; Pyykkoe, Pekka</p> <p>2004-10-01</p> <p>An analytic response theory formulation for the leading-order <span class="hlt">magnetic</span> field-induced and field-dependent quadrupole splitting in nuclear <span class="hlt">magnetic</span> resonance spectra is presented and demonstrated with first-principles calculations for {sup 21}Ne, {sup 36}Ar, and {sup 83}Kr in noble gas <span class="hlt">atoms</span>. The case of molecules was studied for {sup 33}S in the sulphur hexafluoride molecule, as well as for {sup 47/49}Ti, {sup 91}Zr, and {sup 177,179}Hf in group(IV) tetrahalides. According to our calculations, the hitherto experimentally unknown field-induced quadrupole splitting in molecules rises to 10{sup 2} Hz for {sup 177,179}Hf nuclei in HfF{sub 4} and 10{sup 1} Hz for {sup 47/49}Ti in TiCl{sub 4}, and is hence of observable magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707438','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4707438"><span id="translatedtitle">Tunable <span class="hlt">atomic</span> spin-orbit coupling synthesized with a modulating gradient <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Luo, Xinyu; Wu, Lingna; Chen, Jiyao; Guan, Qing; Gao, Kuiyi; Xu, Zhi-Fang; You, L.; Wang, Ruquan</p> <p>2016-01-01</p> <p>We report the observation of synthesized spin-orbit coupling (SOC) for ultracold spin-1 87Rb <span class="hlt">atoms</span>. Different from earlier experiments where a one dimensional (1D) <span class="hlt">atomic</span> SOC of pseudo-spin-1/2 is synthesized with Raman laser fields, the scheme we demonstrate employs a gradient <span class="hlt">magnetic</span> field (GMF) and ground-state <span class="hlt">atoms</span>, thus is immune to <span class="hlt">atomic</span> spontaneous emission. The strength of SOC we realize can be tuned by changing the modulation amplitude of the GMF, and the effect of the SOC is confirmed through the studies of: 1) the collective dipole oscillation of an <span class="hlt">atomic</span> condensate in a harmonic trap after the synthesized SOC is abruptly turned on; and 2) the minimum energy state at a finite adiabatically adjusted momentum when SOC strength is slowly ramped up. The condensate coherence is found to remain very good after driven by modulating GMFs. Our scheme presents an alternative means for studying interacting many-body systems with synthesized SOC. PMID:26752786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...618983L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...618983L"><span id="translatedtitle">Tunable <span class="hlt">atomic</span> spin-orbit coupling synthesized with a modulating gradient <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Xinyu; Wu, Lingna; Chen, Jiyao; Guan, Qing; Gao, Kuiyi; Xu, Zhi-Fang; You, L.; Wang, Ruquan</p> <p>2016-01-01</p> <p>We report the observation of synthesized spin-orbit coupling (SOC) for ultracold spin-1 87Rb <span class="hlt">atoms</span>. Different from earlier experiments where a one dimensional (1D) <span class="hlt">atomic</span> SOC of pseudo-spin-1/2 is synthesized with Raman laser fields, the scheme we demonstrate employs a gradient <span class="hlt">magnetic</span> field (GMF) and ground-state <span class="hlt">atoms</span>, thus is immune to <span class="hlt">atomic</span> spontaneous emission. The strength of SOC we realize can be tuned by changing the modulation amplitude of the GMF, and the effect of the SOC is confirmed through the studies of: 1) the collective dipole oscillation of an <span class="hlt">atomic</span> condensate in a harmonic trap after the synthesized SOC is abruptly turned on; and 2) the minimum energy state at a finite adiabatically adjusted momentum when SOC strength is slowly ramped up. The condensate coherence is found to remain very good after driven by modulating GMFs. Our scheme presents an alternative means for studying interacting many-body systems with synthesized SOC.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=388670','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=388670"><span id="translatedtitle"><span class="hlt">Atomic</span> Regime in Which the <span class="hlt">Magnetic</span> Interaction Dominates the Coulomb Interaction for Highly Excited States of Hydrogen</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mueller, Ronald O.; Hughes, Vernon W.</p> <p>1974-01-01</p> <p>The <span class="hlt">atomic</span> regime in which the interaction of the electron with an external <span class="hlt">magnetic</span> field dominates the Coulomb interaction with the nucleus, relevant to pulsars, can be realized at laboratory <span class="hlt">magnetic</span> fields for discrete autoionized states of hydrogen, at energies above the ionization limit. Approximate wave functions, energy levels, and electric dipole transition probabilities are presented for hydrogen, and an <span class="hlt">atomic</span> beam absorption spectroscopy experiment at 50 kG is proposed to study this new regime. PMID:16578723</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490683','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490683"><span id="translatedtitle">Visualization and quantification of <span class="hlt">magnetic</span> nanoparticles into vesicular systems by combined <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> force microscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dong, C.; Corsetti, S.; Passeri, D.; Rossi, M.; Carafa, M.; Marianecci, C.; Pantanella, F.; Rinaldi, F.; Ingallina, C.; Sorbo, A.</p> <p>2015-06-23</p> <p>We report a phenomenological approach for the quantification of the diameter of <span class="hlt">magnetic</span> nanoparticles (MNPs) incorporated in non-ionic surfactant vesicles (niosomes) using <span class="hlt">magnetic</span> force microscopy (MFM). After a simple specimen preparation, i.e., by putting a drop of solution containing MNPs-loaded niosomes on flat substrates, topography and MFM phase images are collected. To attempt the quantification of the diameter of entrapped MNPs, the method is calibrated on the sole MNPs deposited on the same substrates by analyzing the MFM signal as a function of the MNP diameter (at fixed tip-sample distance) and of the tip-sample distance (for selected MNPs). After calibration, the effective diameter of the MNPs entrapped in some niosomes is quantitatively deduced from MFM images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhST..164a4012Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhST..164a4012Y"><span id="translatedtitle">Visualizing Majorana fermions in a chain of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on a superconductor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yazdani, Ali</p> <p>2015-12-01</p> <p>A chain of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on the surface of a superconductor provides a versatile platform for realizing a one-dimensional topological superconductivity phase with edge-bounded Majorana fermions zero modes. This platform lends itself to spatial resolved measurements with scanning tunneling microscope (STM) that enables direct visualization of the presence of a localized Majorana zero mode. Experiments on self-assembled chains of Fe <span class="hlt">atoms</span> on the surface of Pb show that such a system can be experimentally fabricated and studied using various high-resolution STM measurement techniques. Spatial and energy resolved STM experiments provide strong evidence for Majorana bound states that emerge due to the combination of Fe’s ferromagnetism and spin-orbit coupling of the superconducting Pb substrate. These studies provide a roadmap for optimizing topological superconductivity in this one-dimensional platform and its extension to realize chiral two-dimensional superconductors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22987355','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22987355"><span id="translatedtitle">Protein folding at <span class="hlt">atomic</span> resolution: analysis of autonomously folding supersecondary structure motifs by nuclear <span class="hlt">magnetic</span> resonance.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sborgi, Lorenzo; Verma, Abhinav; Sadqi, Mourad; de Alba, Eva; Muñoz, Victor</p> <p>2013-01-01</p> <p>The study of protein folding has been conventionally hampered by the assumption that all single-domain proteins fold by an all-or-none process (two-state folding) that makes it impossible to resolve folding mechanisms experimentally. Here we describe an experimental method for the thermodynamic analysis of protein folding at <span class="hlt">atomic</span> resolution using nuclear <span class="hlt">magnetic</span> resonance (NMR). The method is specifically developed for the study of small proteins that fold autonomously into basic supersecondary structure motifs, and that do so in the sub-millisecond timescale (folding archetypes). From the NMR experiments we obtain hundreds of <span class="hlt">atomic</span> unfolding curves that are subsequently analyzed leading to the determination of the characteristic network of folding interactions. The application of this approach to a comprehensive catalog of elementary folding archetypes holds the promise of becoming the first experimental approach capable of unraveling the basic rules connecting protein structure and folding mechanism. PMID:22987355</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093575','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093575"><span id="translatedtitle">Experimental study of linear <span class="hlt">magnetic</span> dichroism in photoionization satellite transitions of <span class="hlt">atomic</span> rubidium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jaenkaelae, K.; Alagia, M.; Feyer, V.; Richter, R.; Prince, K. C.</p> <p>2011-11-15</p> <p>Laser orientation in the initial state has been used to study the properties of satellite transitions in inner-shell photoionization of rubidium <span class="hlt">atoms</span>. The linear <span class="hlt">magnetic</span> dichroism in the angular distribution (LMDAD) has been utilized to probe the continuum waves of orbital angular momentum conserving monopole, and angular momentum changing conjugate satellites, accompanying the 4p ionization of <span class="hlt">atomic</span> Rb. We show experimentally that LMDAD of both types of satellite transitions is nonzero and that LMDAD of monopole satellites, measured as a function of photon energy, mimics the LMDAD of direct photoionization, whereas the LMDAD of conjugate transitions deviates drastically from that trend. The results indicate that conjugate transitions cannot be described theoretically without explicit inclusion of electron-electron interaction. The present data can thus be used as a very precise test of current models for photoionization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1227396','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1227396"><span id="translatedtitle">Electric and <span class="hlt">magnetic</span> response in dielectric dark states for low loss subwavelength optical meta <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jain, Aditya; Moitra, Parikshit; Koschny, Thomas; Valentine, Jason; Soukoulis, Costas M.</p> <p>2015-07-14</p> <p>Artificially created surfaces or metasurfaces, composed of appropriately shaped subwavelength structures, namely, meta-<span class="hlt">atoms</span>, control light at subwavelength scales. Historically, metasurfaces have used radiating metallic resonators as subwavelength inclusions. However, while resonant optical metasurfaces made from metal have been sufficiently subwavelength in the propagation direction, they are too lossy for many applications. Metasurfaces made out of radiating dielectric resonators have been proposed to solve the loss problem, but are marginally subwavelength at optical frequencies. We designed subwavelength resonators made out of nonradiating dielectrics. The resonators are decorated with appropriately placed scatterers, resulting in a meta-<span class="hlt">atom</span> with an engineered electromagnetic response. A metasurface that yields an electric response is fabricated, experimentally characterized, and a method to obtain a <span class="hlt">magnetic</span> response at optical frequencies is theoretically demonstrated. In conclusion, this design methodology paves the way for metasurfaces that are simultaneously subwavelength and low loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1227396-electric-magnetic-response-dielectric-dark-states-low-loss-subwavelength-optical-meta-atoms','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1227396-electric-magnetic-response-dielectric-dark-states-low-loss-subwavelength-optical-meta-atoms"><span id="translatedtitle">Electric and <span class="hlt">magnetic</span> response in dielectric dark states for low loss subwavelength optical meta <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Jain, Aditya; Moitra, Parikshit; Koschny, Thomas; Valentine, Jason; Soukoulis, Costas M.</p> <p>2015-07-14</p> <p>Artificially created surfaces or metasurfaces, composed of appropriately shaped subwavelength structures, namely, meta-<span class="hlt">atoms</span>, control light at subwavelength scales. Historically, metasurfaces have used radiating metallic resonators as subwavelength inclusions. However, while resonant optical metasurfaces made from metal have been sufficiently subwavelength in the propagation direction, they are too lossy for many applications. Metasurfaces made out of radiating dielectric resonators have been proposed to solve the loss problem, but are marginally subwavelength at optical frequencies. We designed subwavelength resonators made out of nonradiating dielectrics. The resonators are decorated with appropriately placed scatterers, resulting in a meta-<span class="hlt">atom</span> with an engineered electromagnetic response. Amore » metasurface that yields an electric response is fabricated, experimentally characterized, and a method to obtain a <span class="hlt">magnetic</span> response at optical frequencies is theoretically demonstrated. In conclusion, this design methodology paves the way for metasurfaces that are simultaneously subwavelength and low loss.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhLA..262..476S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhLA..262..476S"><span id="translatedtitle">Two <span class="hlt">magnetic</span> states of iron <span class="hlt">atoms</span> in Invar Fe-Ni alloys and positron annihilation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sedov, V. L.; Tsigel'nik, O. A.</p> <p>1999-11-01</p> <p>The temperature dependence of angular correlation annihilation radiation (ACAR) in Invar Fe-Ni alloys is investigated. It is found that the ACAR distribution in the Curie temperature region TC depends on temperature. This effect is created only by those positrons that are trapped by vacancies. The effect is enhanced if the positrons trapped by vacancy-hydrogen complexes. The ACAR distribution is changed due to enhanced interaction of these positrons with 3d electrons. A simple interpretation of this phenomenon can be given on the basis of the model of two <span class="hlt">magnetic</span> states of Fe <span class="hlt">atoms</span> in Invar alloys. According to this model the enhancement of the electron-positron correlation interaction in the TC region occurs as a result of the convergence of the energy levels εHS and εLS corresponding to the high-spin (HS) and low-spin (LS) states of Fe <span class="hlt">atoms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EL.....9823001H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EL.....9823001H"><span id="translatedtitle"><span class="hlt">Atom</span>-surface interaction at the nanometre scale: van der Waals-Zeeman transitions in a <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamamda, M.; Boustimi, M.; Bocvarski, V.; Taillandier-Loize, T.; Dutier, G.; Perales, F.; Baudon, J.; Ducloy, M.</p> <p>2012-04-01</p> <p>van der Waals-Zeeman transitions between <span class="hlt">magnetic</span> states of metastable rare-gas <span class="hlt">atoms</span> Ar*, Kr* and Xe* (3P2) induced by a solid surface in the presence of a <span class="hlt">magnetic</span> field, are investigated theoretically and experimentally. By use of a Zeeman slower, metastable argon <span class="hlt">atoms</span> with various velocities ranging from 170 to 560 m/s allow us to investigate the small impact parameter range (3-7 nm) within which these transitions occur, as well as the effect of <span class="hlt">atom</span> polarisation on the sharing out of the M states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22029893','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22029893"><span id="translatedtitle">Ionization of helium <span class="hlt">atoms</span> under the effect of the antineutrino <span class="hlt">magnetic</span> moment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martemyanov, V. P. Tsinoev, V. G.</p> <p>2011-12-15</p> <p>Differential cross sections for inelastic antineutrino interaction with a helium <span class="hlt">atom</span> are calculated. It is shown that, in the energy-transfer range extending up to 1 keV, the cross sections in question are considerably enhanced in the electromagnetic-interaction channel in relation to the cross sections for elastic scattering on a free electron. Absolute cross-section values are of interest in searches for the antineutrino <span class="hlt">magnetic</span> moment, provided that its value in Bohr magneton units falls within the range (10{sup -13}-10{sup -12}){sub Micro-Sign B}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/538497','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/538497"><span id="translatedtitle">Discrete variable representation for highly excited states of hydrogen <span class="hlt">atoms</span> in <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grozdanov, T.P.; Andric, L.; Manescu, C.; McCarroll, R.; Grozdanov, T.P.</p> <p>1997-09-01</p> <p>A discrete variable representation (DVR) appropriate for describing the highly excited states of hydrogen <span class="hlt">atoms</span> in laboratory-strength <span class="hlt">magnetic</span> fields is constructed by using a symmetry-adapted direct product of one-dimensional DVR{close_quote}s in parabolic coordinates related to generalized Gauss-Laguerre quadratures. The resulting sparse Hamiltonian matrix is used in an iterative (filter-diagonalization) procedure to obtain eigenvalues and eigenvectors in a given spectral domain. The method is applied to calculate eigenvalues and lifetimes of {open_quotes}circular{close_quotes} Rydberg states, as well as oscillator strengths for the excitation of highly excited states. {copyright} {ital 1997} {ital The American Physical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MPLB...2950248Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MPLB...2950248Y"><span id="translatedtitle">Quantum chaos and statistical properties of energy levels for <span class="hlt">atom</span> in parallel electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Hai-Feng; Tan, Yong-Gang; Liu, Zhong-Li; Fu, Hong-Zhi</p> <p>2015-12-01</p> <p>In this paper, the statistical properties of energy levels are studied numerically for <span class="hlt">atom</span> in parallel electric and <span class="hlt">magnetic</span> fields, which is an ideal system to examine the contributions of external fields and ionic core to quantum chaos. The Stark maps of diamagnetic spectra and nearest neighbor spacing (NNS) distributions are obtained by diagonalization method incorporating core effect. We identify obvious level anti-crossing and large value of q for barium, indicating that core effect has predominant contribution to chaotic dynamics in barium. To study the core effect in detail, we sweep the quantum defect artificially and find that larger core effect will undoubtedly induce stronger chaotic dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304149','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304149"><span id="translatedtitle"><span class="hlt">Magnetic</span> property of transition metal-Si <span class="hlt">atomic</span> line on silicon Σ3 grain boundary: A theoretical study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, Yong-Hua Guo, Shu-Kuan; Ma, Zhong-Quan; Qu, Guo-Hui; Shi, Ting-Ting; Xia, Qin; Gong, Xin-Gao; Wei, Su-Huai</p> <p>2014-06-14</p> <p>Using first-principles calculations within density functional theory, we investigate the electronic and <span class="hlt">magnetic</span> properties of different 3d transition metal-Si <span class="hlt">atomic</span> lines on silicon Σ3 (112) grain boundary, which can be formed through grain boundary segregation. We find that (i) Fe <span class="hlt">atoms</span> occupy the substitutional sites at the grain boundary and form an Fe-Si <span class="hlt">atomic</span> line, but the interaction between the Fe <span class="hlt">atoms</span> is antiferromagnetic. (ii) The ferromagnetic stability increases with the <span class="hlt">atomic</span> number of the transition metals and Co-Si <span class="hlt">atomic</span> line is more stable in the ferromagnetic phase and shows a semimetallic behavior. We suggest that this special TM-Si <span class="hlt">atomic</span> line formed by thermodynamically favorable transition metal segregation on Si grain boundary could be used in design of spin-dependent quantum devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985Ap%26SS.117..309S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985Ap%26SS.117..309S"><span id="translatedtitle">Gamma-quanta conversion into positronium <span class="hlt">atoms</span> in a strong <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shabad, A. E.; Usov, V. V.</p> <p>1985-12-01</p> <p>The formation of mixed photon-positronium states in a strong <span class="hlt">magnetic</span> field near a pulsar and photon capture by the field are studied. Before the photon reaches the threshold of free pair creation, the curvature gamma quanta emitted in the pulsar magnetosphere tangentially to the curved lines of force are shown to be canalized by a field stronger than four trillion G by gradual conversion into a positronium <span class="hlt">atom</span>. This positronium is stable against the ionizing action of the electric field near the pulsar unless it reaches a critical value of about 40 million CGSE for B of about 10 trillion G. This prevents the screening of the electric field up to distances from the pulsar where the <span class="hlt">magnetic</span> field is below 0.1 B(cr) and free pair creation may become essential. This effect provides a higher theoretical estimate for the total luminosity of pulsars whose field at the surface exceeds 0.1 B(cr).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6851821','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6851821"><span id="translatedtitle">Circular Rydberg States of the Hydrogen <span class="hlt">Atom</span> in a <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Germann, T.C.; Herschbach, D.R. ); Dunn, M.; Watson, D.K. )</p> <p>1995-01-30</p> <p>Dimensional perturbation theory is used to study circular Rydberg states ([vert bar][ital m][vert bar]=[ital n][minus]1[much gt]1) and other large [vert bar][ital m][vert bar] states of the hydrogen <span class="hlt">atom</span> in a uniform <span class="hlt">magnetic</span> field. Because of a degeneracy between states of increased angular momentum and states of increased Cartesian dimensionality, the accuracy of the zeroth-order [ital D][r arrow][infinity] limit and a dimensional perturbation expansion improves significantly for states with larger [vert bar][ital m][vert bar]. In contrast to other approaches, this method is applicable to the entire range of <span class="hlt">magnetic</span> field strengths. Energies and expectation values are presented as functions of the field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17764308','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17764308"><span id="translatedtitle">Demonstration of high-performance compact <span class="hlt">magnetic</span> shields for chip-scale <span class="hlt">atomic</span> devices.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Donley, E A; Hodby, E; Hollberg, L; Kitching, J</p> <p>2007-08-01</p> <p>We have designed and tested a set of five miniature nested <span class="hlt">magnetic</span> shields constructed of high-permeability material, with external volumes for the individual shielding layers ranging from 0.01 to 2.5 cm(3). We present measurements of the longitudinal and transverse shielding factors (the ratio of external to internal <span class="hlt">magnetic</span> field) of both individual shields and combinations of up to three layers. The largest shielding factor measured was 6 x 10(6) for a nested set of three shields, and from our results we predict a shielding factor of up to 1 x 10(13) when all five shields are used. Two different techniques were used to measure the internal field: a chip-scale <span class="hlt">atomic</span> magnetometer and a commercially available magnetoresistive sensor. Measurements with the two methods were in good agreement. PMID:17764308</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyB..489...51X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyB..489...51X"><span id="translatedtitle"><span class="hlt">Magnetic</span> properties and <span class="hlt">atomic</span> ordering of BCC Heusler alloy Fe2MnGa ribbons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xin, Yuepeng; Ma, Yuexing; Luo, Hongzhi; Meng, Fanbin; Liu, Heyan</p> <p>2016-05-01</p> <p>The electronic structure, <span class="hlt">atomic</span> disorder and <span class="hlt">magnetic</span> properties of the Heusler alloy Fe2MnGa have been investigated experimentally and theoretically. BCC Fe2MnGa ribbon samples were prepared. Experimentally, a saturation <span class="hlt">magnetic</span> moment (3.68 μB at 5 K) much larger than the theoretical value (2.04 μB) has been reported. First-principles calculations indicate that the difference is related to the Fe-Mn disorder between A, B sites, as can also be deduced from the XRD pattern. L21 type Fe2MnGa is a ferrimagnet with antiparallel Fe and Mn spin moments. However, when Fe-Mn disorder occurs, part of Mn moments will be parallel to Fe moments, and the Fe moments also clearly increase simultaneously. All this results in a total moment of 3.74 μB, close to the experimental value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20699285','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20699285"><span id="translatedtitle">Tunable <span class="hlt">Atomic</span> Magnetometer for Detection of Radio-Frequency <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Savukov, I.M.; Seltzer, S.J.; Romalis, M.V.; Sauer, K.L.</p> <p>2005-08-05</p> <p>We describe an alkali-metal magnetometer for detection of weak <span class="hlt">magnetic</span> fields in the radio-frequency (rf) range. High sensitivity is achieved by tuning the Zeeman resonance of alkali <span class="hlt">atoms</span> to the rf frequency and partially suppressing spin-exchange collisions in the alkali-metal vapor. We demonstrate <span class="hlt">magnetic</span> field sensitivity of 2 fT/Hz{sup 1/2} at a frequency of 99 kHz with a resonance width of 400 Hz. We also derive a simple analytic expression for the fundamental limit on the sensitivity of the rf magnetometer and show that a sensitivity of about 0.01 fT/Hz{sup 1/2} can be achieved in a practical system with a measurement volume of 200 cm{sup 3}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MART23015C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MART23015C"><span id="translatedtitle"><span class="hlt">Atomic</span> Structures and <span class="hlt">Magnetic</span> Properties of Fe-rich Fe1-xCox Alloys: A Genetic Algorithm Search</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuong Nguyen, Manh; Zhao, Xin; Ji, Min; Harmon, Bruce; Wang, Cai-Zhuang; Ho, Kai-Ming</p> <p>2012-02-01</p> <p>Using genetic algorithm with first-principles calculations, we performed a broad global search for low-energy crystal structures of Fe-rich Fe1-xCox alloys. We found that Fe-rich Fe1-xCox alloys are highly configurationally degenerate and there are many additional off-stoichiometric stable structures to the well-known stoichiometric FeCo - B2 structure, giving a possibility for atomistic manipulation of the alloys. The Co-Co nearest-neighbor pair is strongly unfavorable in Fe-rich Fe1-xCox alloys. The <span class="hlt">magnetic</span> moment of Fe <span class="hlt">atom</span> is increasing with Co concentration while that of Co <span class="hlt">atom</span> is almost constant, inducing a Slater-Pauling curve for <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span>. The <span class="hlt">magnetic</span> moment of Fe <span class="hlt">atom</span> is strongly dependent on the number of Co nearest-neighbors and it increases with this number.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ApPhL..82.2236S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ApPhL..82.2236S"><span id="translatedtitle">Determination of radiation exposure history of common materials and computer hardware by using <span class="hlt">atomic</span> (and <span class="hlt">magnetic</span> force) microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, J.; Teter, J. P.; Abbundi, R. J.; Guardala, N. A.</p> <p>2003-04-01</p> <p>Defects produced by ionizing radiation are smaller than a micrometer and are unobservable in an optical microscope. An <span class="hlt">atomic</span> force microscope was utilized to reveal their counts and structure in common materials like mica, silicon, organic solids, polymers, sugar, quartz, and calcite. A <span class="hlt">magnetic</span> force microscope has shown the damage of radiation on computer hard disks. The present work shows that exposure to radioactive material leaves a permanent record, which can be read for dosimetric or forensic purposes by using <span class="hlt">atomic</span> force microcopy on common objects or a <span class="hlt">magnetic</span> force microscope on <span class="hlt">magnetic</span> media.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3535417','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3535417"><span id="translatedtitle"><span class="hlt">Atomic</span>-scale engineering of <span class="hlt">magnetic</span> anisotropy of nanostructures through interfaces and interlines</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ouazi, S.; Vlaic, S.; Rusponi, S.; Moulas, G.; Buluschek, P.; Halleux, K.; Bornemann, S.; Mankovsky, S.; Minár, J.; Staunton, J.B.; Ebert, H.; Brune, H.</p> <p>2012-01-01</p> <p>The central goals of nanoscale <span class="hlt">magnetic</span> materials science are the self-assembly of the smallest structure exhibiting ferromagnetic hysteresis at room temperature, and the assembly of these structures into the highest density patterns. The focus has been on chemically ordered alloys combining <span class="hlt">magnetic</span> 3d elements with polarizable 5d elements having high spin–orbit coupling and thus yielding the desired large magneto-crystalline anisotropy. The chemical synthesis of nanoparticles of these alloys yields disordered phases requiring annealing to transform them to the high-anisotropy L10 structure. Despite considerable efforts, so far only part of the nanoparticles can be transformed without coalescence. Here we present an alternative approach to homogeneous alloys, namely the creation of nanostructures with <span class="hlt">atomically</span> sharp bimetallic interfaces and interlines. They exhibit unexpectedly high <span class="hlt">magnetization</span> reversal energy with values and directions of the easy <span class="hlt">magnetization</span> axes strongly depending on chemistry and texture. We find significant deviations from the expected behaviour for commonly used element combinations. Ab-initio calculations reproduce these results and unravel their origin. PMID:23271648</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22409951','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22409951"><span id="translatedtitle">Large perpendicular <span class="hlt">magnetic</span> anisotropy of single Co <span class="hlt">atom</span> on MgO monolayer: A first-principles study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shao, Bin; Shi, Wu-Jun; Feng, Min; Zuo, Xu</p> <p>2015-05-07</p> <p>Realizing the <span class="hlt">magnetic</span> bit with a single <span class="hlt">atom</span> is the ultimate goal for <span class="hlt">magnetic</span> storage. Based on density functional theory, the <span class="hlt">magnetic</span> anisotropy (MA) of single Co <span class="hlt">atom</span> on MgO monolayer has been investigated. Results show that this two dimensional system possesses a large perpendicular MA, about 5.8 meV per Co <span class="hlt">atom</span>. Besides, there exists remarkable unquenched orbital moments for different <span class="hlt">magnetization</span> directions, which can be attributed to the reduction of coordination number in two dimensional system and is responsible for the enhanced MA. The Bloch pseudo-wavefunction and band structure of Co d-orbitals have been calculated to elucidate the origin of the perpendicular MA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ChPhL..27b3201W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ChPhL..27b3201W"><span id="translatedtitle">Dynamics of a Rydberg Hydrogen <span class="hlt">Atom</span> in a Generalized van der Waals Potential and a <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, De-Hua</p> <p>2010-02-01</p> <p>The classical dynamics of a Rydberg hydrogen <span class="hlt">atom</span> in a generalized van der Waals potential plus a <span class="hlt">magnetic</span> field is investigated by using the Poincaré surface of section and phase space trajectories method. The dynamical character of this system depends sensitively on the <span class="hlt">magnetic</span> field strength. The numerical calculations show that for a certain van der Waals potential, its classical dynamics is regular without the external <span class="hlt">magnetic</span> field. However, with the addition of the external <span class="hlt">magnetic</span> field, the dynamical property of the Rydberg hydrogen <span class="hlt">atom</span> begins to change. With the increase of the <span class="hlt">magnetic</span> field strength, order-chaos-order-chaos types of transition regions are observed for the hydrogen <span class="hlt">atom</span>. As the <span class="hlt">magnetic</span> field strength is very large, nearly all the phase space trajectories are chaotic. Under this condition, only chaotic motion appears. This is caused by the diamagnetic Zeeman effect. Our study provides a different perspective on the dynamical behavior of the Rydberg <span class="hlt">atom</span> in the van der Waals potential and <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARE27008Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARE27008Y"><span id="translatedtitle">Visualization of Ce <span class="hlt">atoms</span> and surface-induced <span class="hlt">magnetism</span> in CeCoIn5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoshida, Yasuo; Kim, Howon; Lee, Chi-Cheng; Lin, Hsin; Haga, Yoshinori; Tateiwa, Naoyuki; Fisk, Zachary; Hasegawa, Yukio</p> <p></p> <p>CeCoIn5 is known as a heavy fermion compound naturally born at the quantum critical point having an unconventional d-wave superconducting phase at low temperatures. Recently, several STM works on a cleaved surface of this compound reported visualization of emerging heavy fermion bands and consistency of the bulk superconducting properties reported previously. However, reported STM images in those works only visualized In <span class="hlt">atoms</span> on the Ce-In plane even though the Ce-In plane contains Ce and In <span class="hlt">atoms</span>. By performing precise low-temperature STM measurements on CeCoIn5, we successfully visualize Ce <span class="hlt">atoms</span> on the Ce-In plane and, in addition, surface-induced staggered dumbblell-shaped order on the Co plane. This ordered structure locally has C2v symmetry but retaining C4 symmetry. This structure coexists with the superconductivity, and is robust against temperatures (>Tc) and an external <span class="hlt">magnetic</span> field (>Hc2) . In the talk, we will discuss the origin of the peculiar ordered structure based on our experimental observations together with first principles calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..93e3404R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..93e3404R"><span id="translatedtitle">Strong-field <span class="hlt">atomic</span> ionization in an elliptically polarized laser field and a constant <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rylyuk, V. M.</p> <p>2016-05-01</p> <p>Within the framework of the quasistationary quasienergy state (QQES) formalism, the tunneling and multiphoton ionization of <span class="hlt">atoms</span> and ions subjected to a perturbation by a high intense laser radiation field of an arbitrary polarization and a constant <span class="hlt">magnetic</span> field are considered. On the basis of the exact solution of the Schrödinger equation and the Green's function for the electron moving in an arbitrary laser field and crossed constant electric and <span class="hlt">magnetic</span> fields, the integral equation for the complex quasienergy and the energy spectrum of the ejected electron are derived. Using the "imaginary-time" method, the extremal subbarrier trajectory of the photoelectron moving in a nonstationary laser field and a constant <span class="hlt">magnetic</span> field are considered. Within the framework of the QQES formalism and the quasiclassical perturbation theory, ionization rates when the Coulomb interaction of the photoelectron with the parent ion is taken into account at arbitrary values of the Keldysh parameter are derived. The high accuracy of rates is confirmed by comparison with the results of numerical calculations. Simple analytical expressions for the ionization rate with the Coulomb correction in the tunneling and multiphoton regimes in the case of an elliptically polarized laser beam propagating at an arbitrary angle to the constant <span class="hlt">magnetic</span> field are derived and discussed. The limits of small and large <span class="hlt">magnetic</span> fields and low and high frequency of a laser field are considered in details. It is shown that in the presence of a nonstationary laser field perturbation, the constant <span class="hlt">magnetic</span> field may either decrease or increase the ionization rate. The analytical consideration and numerical calculations also showed that the difference between the ionization rates for an s electron in the case of right- and left-elliptically polarized laser fields is especially significant in the multiphoton regime for not-too-high <span class="hlt">magnetic</span> fields and decreases as the <span class="hlt">magnetic</span> field increases. The paper generalizes the results obtained earlier [V. M. Rylyuk, Phys. Rev. A 86, 013402 (2012), 10.1103/PhysRevA.86.013402].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PTEP.2014c3A01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PTEP.2014c3A01S"><span id="translatedtitle">Electric and <span class="hlt">magnetic</span> dipole allowed transitions of <span class="hlt">atoms</span> for three-dimensionally isotropic left handedness in a mixed <span class="hlt">atomic</span> vapor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Jian Qi</p> <p>2014-03-01</p> <p>Since previous negative-index <span class="hlt">atomic</span> media based on quantum optical approaches are highly lossy, a proposal for realizing a three-dimensionally isotropic left-handed <span class="hlt">atomic</span> vapor medium is suggested based on a mechanism of incoherent gain assisted <span class="hlt">atomic</span> transitions. Two three-level <span class="hlt">atomic</span> systems are utilized for producing simultaneously negative permittivity and negative permeability, respectively, in the same frequency band. We suggest that fine and hyperfine level transitions of <span class="hlt">atoms</span> (e.g., a hyperfine level transition in a hydrogen <span class="hlt">atomic</span> system and a fine level transition in an alkali-metal <span class="hlt">atomic</span> system) would be applicable to realization of such a negatively refracting <span class="hlt">atomic</span> vapor. The attractive features of the present scenario include: i) three-dimensionally isotropic negative indices; ii) incoherent gain wave amplification in the negative-index <span class="hlt">atomic</span> vapor; iii) tunable negative indices depending upon external fields. Such a left-handed quantum optical medium can serve as a supporting substrate for lossy negative-index materials for loss compensation. It can also be used in designing new quantum optical and photonic devices (e.g., a subwavelength focusing system and a negative-index superlens for perfect imaging) because of its attractive properties of three-dimensional isotropy and high-gain wave amplification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvB..85v4406U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvB..85v4406U"><span id="translatedtitle">Interface <span class="hlt">atomic</span> structures and <span class="hlt">magnetic</span> anisotropy of Fe and Pd/Fe monatomic films on Pd(001)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ueno, Tetsuro; Sawada, Masahiro; Furumoto, Kazuhito; Tagashira, Tetsuro; Tohoda, Satoshi; Kimura, Akio; Haraguchi, Shinya; Tsujikawa, Masahito; Oda, Tatsuki; Namatame, Hirofumi; Taniguchi, Masaki</p> <p>2012-06-01</p> <p>The <span class="hlt">magnetic</span> anisotropy of monatomic Fe films on Pd(001) with or without a Pd overlayer was investigated from the standpoint of interface <span class="hlt">atomic</span> structures. Quantitative analysis included low-energy electron diffraction and x-ray <span class="hlt">magnetic</span> circular dichroism (XMCD) experiments, and first-principles calculations were also performed on monatomic Fe and Pd/Fe systems. It was revealed that Fe <span class="hlt">atoms</span> intermix with the Pd substrate at room temperature. A spin reorientation transition occurs at a critical Fe thickness of 1.2 monolayers (ML) in Fe/Pd(001), while in-plane <span class="hlt">magnetic</span> anisotropy is persistent in Pd/Fe/Pd(001) throughout the entire sample. The Fe 3d spin and orbital <span class="hlt">magnetic</span> moments for both systems are strongly enhanced near 1 ML Fe thickness, as compared to those of the bulk iron crystal. In addition, an induced <span class="hlt">magnetic</span> moment in interfacial Pd <span class="hlt">atoms</span> was observed by XMCD at the Pd M2,3 core absorption edges. It was concluded that the L10-like tetragonally distorted interface <span class="hlt">atomic</span> structure in monatomic Fe/Pd(001) induces the perpendicular <span class="hlt">magnetic</span> anisotropy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10175853','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10175853"><span id="translatedtitle">RHIC <span class="hlt">warm</span>-bore systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Welch, K.M.</p> <p>1994-07-01</p> <p>Pressure profiles, in time, are calculated as a consequence of anticipated outgassing of various beam components (e.g., rf cavities, etc.) and <span class="hlt">warm</span>-bore beam pipes. Gold beam lifetimes and transverse beam emittance growth are given for calculated average pressures. Examples of undesirable <span class="hlt">warm</span>-bore conditions are presented such as contaminated experimental beam pipes and <span class="hlt">warm</span>-bore <span class="hlt">magnets</span> (i.e., DX). These examples may prove instructive. The methods used in making these calculations are presented in Section 2. They are applicable to all linear systems. The calculations given apply to the RHIC accelerator and more specifically to <span class="hlt">warm</span>-bore regions of the machine.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21405914','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21405914"><span id="translatedtitle">Variational-average-<span class="hlt">atom</span>-in-quantum-plasmas (VAAQP) code and virial theorem: equation-of-state and shock-Hugoniot calculations for <span class="hlt">warm</span> dense Al, Fe, Cu, and Pb.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piron, R; Blenski, T</p> <p>2011-02-01</p> <p>The numerical code VAAQP (variational average <span class="hlt">atom</span> in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-<span class="hlt">atom</span> structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the <span class="hlt">warm</span>-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-<span class="hlt">atom</span> models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included. PMID:21405914</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...588A.131G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...588A.131G"><span id="translatedtitle"><span class="hlt">Warm</span> ISM in the Sagittarius A Complex. I. Mid-J CO, <span class="hlt">atomic</span> carbon, ionized <span class="hlt">atomic</span> carbon, and ionized nitrogen sub-mm/FIR line observations with the Herschel-HIFI and NANTEN2/SMART telescopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García, P.; Simon, R.; Stutzki, J.; Güsten, R.; Requena-Torres, M. A.; Higgins, R.</p> <p>2016-04-01</p> <p>Aims: We investigate the spatial and spectral distribution of the local standard of rest (LSR) velocity resolved submillimetre emission from the <span class="hlt">warm</span> (25-90 K) gas in the Sgr A Complex, located in the Galactic centre. Methods: We present large-scale submillimetre heterodyne observations towards the Sgr A Complex covering ~300 arcmin2. These data were obtained in the frame of the Herschel EXtraGALactic guaranteed time key program (HEXGAL) with the Herschel-HIFI satellite and are complemented with submillimetre observations obtained with the NANTEN2/SMART telescope as part of the NANTEN2/SMART Central Nuclear Zone Survey. The observed species are CO(J = 4-3) at 461.0 GHz observed with the NANTEN2/SMART telescope, and [CI] 3P1-3P0 at 492.2 GHz, [CI] 3P2-3P1 at 809.3 GHz, [NII] 3P1-3P0 at 1461.1 GHz, and [CII] 2P3/2-2P1/2 at 1900.5 GHz observed with the Herschel-HIFI satellite. The observations are presented in a 1 km s-1 spectral resolution and a spatial resolution ranging from 46 arcsec to 28 arcsec. The spectral coverage of the three lower frequency lines is ±200 km s-1, while in the two high frequency lines, the upper LSR velocity limit is +94 km s-1 and +145 km s-1 for the [NII] and [CII] lines, respectively. Results: The spatial distribution of the emission in all lines is very widespread. The bulk of the carbon monoxide emission is found towards Galactic latitudes below the Galactic plane, and all the known molecular clouds are identified. Both neutral <span class="hlt">atomic</span> carbon lines have their brightest emission associated with the +50 km s-1 cloud. Their spatial distribution at this LSR velocity describes a crescent-shape structure, which is probably the result of interaction with the energetic event (one or several supernovae explosions) that gave origin to the non-thermal Sgr A-East source. The [CII] and [NII] emissions have most of their flux associated with the thermal arched-filaments and the H region and bright spots in [CII] emission towards the central nuclear disk (CND) are detected. <span class="hlt">Warm</span> Gas at very high (|Vlsr|> 100 km s-1) LSR velocities is also detected towards the line of sight to the Sgr A Complex, and it is most probably located outside the region, in the X1 orbits. All data cubes presented in the paper (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A131Channel maps are availalble at http://https://www.astro.uni-koeln.de/online-data/Garcia_P_SgrA_AA588/</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22156293','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22156293"><span id="translatedtitle"><span class="hlt">Atomic</span> disorder and the <span class="hlt">magnetic</span>, electrical, and optical properties of a Co{sub 2}CrAl Heusler alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Svyazhin, A. D. Shreder, E. I.; Voronin, V. I.; Berger, I. F.; Danilov, S. E.</p> <p>2013-03-15</p> <p>Two Co{sub 2}CrAl alloy samples subjected to different heat treatment regimes are studied. An exact distribution of <span class="hlt">atoms</span> over the sublattices in the samples is determined by X-ray diffraction and neutron diffraction methods. These data are used to perform ab initio density of states calculations and to calculate the <span class="hlt">magnetic</span> moments of the samples in a coherent potential approximation. The calculated <span class="hlt">magnetic</span> moments are compared to the experimental values. The effect of <span class="hlt">atomic</span> ordering on the electronic structure near the Fermi level is analyzed using optical methods. The possible causes of the detected temperature dependence of the electrical resistivity, unusual for metallic alloys, are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18328755','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18328755"><span id="translatedtitle">Structural, electronic, and <span class="hlt">magnetic</span> properties of heterofullerene C(58)Si with odd number of <span class="hlt">atoms</span> and a near planar tetracoordinate Si <span class="hlt">atom</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Feng-Ling; Jalbout, Abraham F</p> <p>2008-06-01</p> <p>Density functional calculations and minimization techniques have been employed to characterize the structural and electronic properties of [5,6]-heterofullerene-C(58)Si-C(2v). Since it has odd number of <span class="hlt">atoms</span> and a near planar tetracoordinate Si <span class="hlt">atom</span> on the skeleton of the cage, it has odd number of <span class="hlt">atoms</span> assembling a cage and is a novel molecule. Vibrational frequencies of the molecule have been calculated at the B3LYP/6-31G* level of theory. The absence of imaginary vibrational frequency confirms that the molecule corresponds to a true minimum on the potential energy hypersurface. Sixteen (13)C nuclear <span class="hlt">magnetic</span> resonance (NMR) spectral signals of C(58)Si are characterized, and its heat of formation was estimated in this work. PMID:18328755</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhLA..377.2147A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhLA..377.2147A"><span id="translatedtitle"><span class="hlt">Magnetic</span> silicon carbide nanotubes by 3d transition metal <span class="hlt">atom</span> functionalization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adhikari, Kapil; Ray, Asok K.</p> <p>2013-11-01</p> <p>Interaction of 3d transition metal <span class="hlt">atoms</span> with (3,3), (5,5), (7,7), and (9,9) SiC nanotubes has been studied using hybrid density functional PBE0 and an all electron basis set 6-31G. The interaction energy between transition metal and silicon carbide nanotubes depends both on the number of d-electrons and on the curvature of the nanotubes, with this energy, in general, increasing with increase in curvature. Except for the nanotubes functionalized by Ni and Zn, all 3d transition metal-functionalized nanotubes indicate <span class="hlt">magnetic</span> ground states. The silicon carbide nanotubes doped with transition metals have significantly lower band gaps, in general, than those of bare nanotubes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20898658','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20898658"><span id="translatedtitle">Quantum and Classical Description of H <span class="hlt">Atom</span> Under <span class="hlt">Magnetic</span> Field and Quadrupole Trap Potential</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mahecha, J.; Salas, J. P.</p> <p>2006-12-01</p> <p>A discussion regarding the energy levels spectrum of quantum systems whose classical analogous has states of chaotic motion is presented. The chaotic dynamics of the classical underlying system has its manifestation in the wave functions (in the form of 'scars') and in the energy levels (in the form of 'statistical repulsion' of the energy levels). The above mentioned signatures are named 'quantum chaos'. A typical study of quantum chaos requires finding accurate energy eigenvalues of highly excited states, to calculate the nearest neighbors spacing between levels, to perform the 'unfolding' of the spectrum in order to separate the fluctuations, and finally to find the probability distribution of the unfolded spectrum. This is exemplified by the hydrogen <span class="hlt">atom</span> under uniform <span class="hlt">magnetic</span> field and a quadrupole electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22039807','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22039807"><span id="translatedtitle"><span class="hlt">Magnetically</span>-modulated <span class="hlt">atomic</span> force microscopy for analysis of soft matter systems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kageshima, Masami</p> <p>2012-11-01</p> <p>Experimental method of studying viscoelasticity, a common idea to understand properties of microscopic biological soft matter systems, especially single biopolymer chains, using <span class="hlt">atomic</span> force microscopy (AFM) with <span class="hlt">magnetically</span>- driven cantilever is surveyed. The experimental setup of applying well-characterized excitation to the cantilever and the analysis method to derive the viscoelasticity of the system under study are briefly introduced. Examples of measuring viscoelasticity of single peptide molecule and single titin molecule are shown. Considering the close relation of viscoelasticity and the time-scale for nonequilibrium dynamics in soft matter, extension of the method to a frequency-resolved analysis is attempted. A result of measuring viscoelasticity spectrum of a single dextran chain is shown. Challenges in further progress of the method are also described. PMID:22039807</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22146013','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22146013"><span id="translatedtitle">Atmospheric chemistry of isoflurane, desflurane, and sevoflurane: kinetics and mechanisms of reactions with chlorine <span class="hlt">atoms</span> and OH radicals and global <span class="hlt">warming</span> potentials.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sulbaek Andersen, Mads P; Nielsen, Ole J; Karpichev, Boris; Wallington, Timothy J; Sander, Stanley P</p> <p>2012-06-21</p> <p>The smog chamber/Fourier-transform infrared spectroscopy (FTIR) technique was used to measure the rate coefficients k(Cl + CF(3)CHClOCHF(2), isoflurane) = (4.5 ± 0.8) × 10(-15), k(Cl + CF(3)CHFOCHF(2), desflurane) = (1.0 ± 0.3) × 10(-15), k(Cl + (CF(3))(2)CHOCH(2)F, sevoflurane) = (1.1 ± 0.1) × 10(-13), and k(OH + (CF(3))(2)CHOCH(2)F) = (3.5 ± 0.7) × 10(-14) cm(3) molecule(-1) in 700 Torr of N(2)/air diluent at 295 ± 2 K. An upper limit of 6 × 10(-17) cm(3) molecule(-1) was established for k(Cl + (CF(3))(2)CHOC(O)F). The laser photolysis/laser-induced fluorescence (LP/LIF) technique was employed to determine hydroxyl radical rate coefficients as a function of temperature (241-298 K): k(OH + CF(3)CHFOCHF(2)) = (7.05 ± 1.80) × 10(-13) exp[-(1551 ± 72)/T] cm(3) molecule(-1); k(296 ± 1 K) = (3.73 ± 0.08) × 10(-15) cm(3) molecule(-1), and k(OH + (CF(3))(2)CHOCH(2)F) = (9.98 ± 3.24) × 10(-13) exp[-(969 ± 82)/T] cm(3) molecule(-1); k(298 ± 1 K) = (3.94 ± 0.30) × 10(-14) cm(3) molecule(-1). The rate coefficient of k(OH + CF(3)CHClOCHF(2), 296 ± 1 K) = (1.45 ± 0.16) × 10(-14) cm(3) molecule(-1) was also determined. Chlorine <span class="hlt">atoms</span> react with CF(3)CHFOCHF(2) via H-abstraction to give CF(3)CFOCHF(2) and CF(3)CHFOCF(2) radicals in yields of approximately 83% and 17%. The major atmospheric fate of the CF(3)C(O)FOCHF(2) alkoxy radical is decomposition via elimination of CF(3) to give FC(O)OCHF(2) and is unaffected by the method used to generate the CF(3)C(O)FOCHF(2) radicals. CF(3)CHFOCF(2) radicals add O(2) and are converted by subsequent reactions into CF(3)CHFOCF(2)O alkoxy radicals, which decompose to give COF(2) and CF(3)CHFO radicals. In 700 Torr of air 82% of CF(3)CHFO radicals undergo C-C scission to yield HC(O)F and CF(3) radicals with the remaining 18% reacting with O(2) to give CF(3)C(O)F. Atmospheric oxidation of (CF(3))(2)CHOCH(2)F gives (CF(3))(2)CHOC(O)F in a molar yield of 93 ± 6% with CF(3)C(O)CF(3) and HCOF as minor products. The IR spectra of (CF(3))(2)CHOC(O)F and FC(O)OCHF(2) are reported for the first time. The atmospheric lifetimes of CF(3)CHClOCHF(2), CF(3)CHFOCHF(2), and (CF(3))(2)CHOCH(2)F (sevoflurane) are estimated at 3.2, 14, and 1.1 years, respectively. The 100 year time horizon global <span class="hlt">warming</span> potentials of isoflurane, desflurane, and sevoflurane are 510, 2540, and 130, respectively. The atmospheric degradation products of these anesthetics are not of environmental concern. PMID:22146013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22081081','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22081081"><span id="translatedtitle">Induction of coherent <span class="hlt">magnetization</span> switching in a few <span class="hlt">atomic</span> layers of FeCo using voltage pulses.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shiota, Yoichi; Nozaki, Takayuki; Bonell, Frédéric; Murakami, Shinichi; Shinjo, Teruya; Suzuki, Yoshishige</p> <p>2012-01-01</p> <p>The <span class="hlt">magnetization</span> direction of a metallic <span class="hlt">magnet</span> has generally been controlled by a <span class="hlt">magnetic</span> field or by spin-current injection into nanosized <span class="hlt">magnetic</span> cells. Both these methods use an electric current to control the <span class="hlt">magnetization</span> direction; therefore, they are energy consuming. <span class="hlt">Magnetization</span> control using an electric field is considered desirable because of its expected ultra-low power consumption and coherent behaviour. Previous experimental approaches towards achieving voltage control of <span class="hlt">magnetization</span> switching have used single ferromagnetic layers with and without piezoelectric materials, ferromagnetic semiconductors, multiferroic materials, and their hybrid systems. However, the coherent control of <span class="hlt">magnetization</span> using voltage signals has not thus far been realized. Also, bistable <span class="hlt">magnetization</span> switching (which is essential in information storage) possesses intrinsic difficulties because an electric field does not break time-reversal symmetry. Here, we demonstrate a coherent precessional <span class="hlt">magnetization</span> switching using electric field pulses in nanoscale <span class="hlt">magnetic</span> cells with a few <span class="hlt">atomic</span> FeCo (001) epitaxial layers adjacent to a MgO barrier. Furthermore, we demonstrate the realization of bistable toggle switching using the coherent precessions. The estimated power consumption for single switching in the ideal equivalent switching circuit can be of the order of 10(4)k(B)T, suggesting a reduction factor of 1/500 when compared with that of the spin-current-injection switching process. PMID:22081081</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24584481','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24584481"><span id="translatedtitle">Spin-induced band modifications of graphene through intercalation of <span class="hlt">magnetic</span> iron <span class="hlt">atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sung, S J; Yang, J W; Lee, P R; Kim, J G; Ryu, M T; Park, H M; Lee, G; Hwang, C C; Kim, Kwang S; Kim, J S; Chung, J W</p> <p>2014-04-01</p> <p>Intercalation of <span class="hlt">magnetic</span> iron <span class="hlt">atoms</span> through graphene formed on the SiC(0001) surface is found to induce significant changes in the electronic properties of graphene due mainly to the Fe-induced asymmetries in charge as well as spin distribution. From our synchrotron-based photoelectron spectroscopy data together with ab initio calculations, we observe that the Fe-induced charge asymmetry results in the formation of a quasi-free-standing bilayer graphene while the spin asymmetry drives multiple spin-split bands. We find that Fe adatoms are best intercalated upon annealing at 600 °C, exhibiting split linear π-bands, characteristic of a bilayer graphene, but much diffused. Subsequent changes in the C 1s, Si 2p, and Fe 3p core levels are consistently described in terms of Fe-intercalation. Our calculations together with a spin-dependent tight binding model ascribe the diffuse nature of the π-bands to the multiple spin-split bands originated from the spin-injected carbon <span class="hlt">atoms</span> residing only in the lower graphene layer. PMID:24584481</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MAR.B7004Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MAR.B7004Y"><span id="translatedtitle">Topological superconductivity and Majorana fermions in chains of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on the surface of a superconductor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yazdani, Ali</p> <p>2015-03-01</p> <p>Chain of <span class="hlt">magnetic</span> <span class="hlt">atoms</span> on the surface of a BCS superconductor is a versatile platform for the realization of one-dimensional superconductors with Majorana bound states that lends itself to high-resolution scanning tunneling microscopy studies. In this talk, I will describe experimental efforts to realize this platform using self-assembled chains of Fe <span class="hlt">atoms</span> on the surface of Pb (110) and to directly visualize Majorana quasi-particle bound states at their edges. Using spin-polarized STM studies, we show that Fe chains are ferromagnetic while tunneling into Pb's substrate demonstrates signatures of strong spin-orbit interaction at its surface. Comparison of experimental measurements of structure and normal state electronic structure with DFT calculations suggest that these are triple zigzag chains with an odd number of band-crossings at the Fermi level. The onset of superconductivity in the Pb strongly modifies the low energy density of states of the Fe chains and induces a zero energy state at their ends. I will describe how these observations are consistent with the formation of a topological superconducting phase with Majorana edge states. Work supported by ONR, NSF-DMR, NSF-MRSEC, ARO-MURI, and LPS-ARO grants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25360963','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25360963"><span id="translatedtitle">Investigation of electric/<span class="hlt">magnetic</span> local interaction between Si photonic-crystal nanocavities and Au meta-<span class="hlt">atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yi, Yoonsik; Asano, Takashi; Tanaka, Yoshinori; Song, Bong-Shik; Noda, Susumu</p> <p>2014-10-01</p> <p>We experimentally investigate nanoscale local interaction in a composite system consisting of dielectric photonic-crystal nanocavity and metallic meta-<span class="hlt">atoms</span>. The Q factor of the composite system changes by a maximum of about 10 dB based on the relative position and the type of meta-<span class="hlt">atoms</span>. The emission by meta-<span class="hlt">atoms</span> dominates the nanocavity emission when they are in the electric or <span class="hlt">magnetic</span> antinodes of the cavity field. Circularly polarized emission is achieved by tuning the polarization, the position, and the coupling phase of each meta-<span class="hlt">atom</span> with respect to the nanocavity. Utilization of the local interaction with meta-<span class="hlt">atoms</span> is shown to be useful as a new degree of freedom in tailoring the characteristics of nanocavities. PMID:25360963</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhSS...57.1142V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhSS...57.1142V"><span id="translatedtitle">Specific features of the formation of <span class="hlt">atomic</span> <span class="hlt">magnetic</span> moments in amorphous films RE-Co ( RE = La, Gd, Tb)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vas'kovskiy, V. O.; Adanakova, O. A.; Balymov, K. G.; Kulesh, N. A.; Svalov, A. V.; Stepanova, E. A.</p> <p>2015-06-01</p> <p>A systematic investigation of the <span class="hlt">magnetic</span> properties of amorphous films in ( RE) x Co100 - x binary systems in the ground state with rare-earth elements ( RE) of different types has been performed. The concentration dependences of the average <span class="hlt">atomic</span> <span class="hlt">magnetic</span> moments of cobalt ( m Co), gadolinium ( m Gd), and terbium ( m Tb) have been determined from the analysis of the spontaneous <span class="hlt">magnetization</span> of the films with a nonmagnetic rare-earth element (La), a rare-earth element with a spherical electron shell (Gd), and a rareearth element with a large orbital <span class="hlt">magnetic</span> moment (Tb). It has been shown that, in the range 0 < x < 50 at %, the <span class="hlt">magnetic</span> moment m Co decreases from 1.7 ?B to zero, the <span class="hlt">magnetic</span> moment m Gd remains unchanged and almost coincides with the <span class="hlt">magnetic</span> moment of the free <span class="hlt">atom</span> (7 ?B), and the value of m Tb decreases monotonically, but the rate of decrease depends on the method of the sample preparation. The revealed regularities are associated with the concentration change in the electronic structure of cobalt and with the specificity of the <span class="hlt">magnetic</span> structure of the films, which has a ferromagnetic, ferrimagnetic, or sperimagnetic character for samples containing La, Gd, or Tb, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..379..137D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..379..137D"><span id="translatedtitle">A quantitative study of particle size effects in the magnetorelaxometry of <span class="hlt">magnetic</span> nanoparticles using <span class="hlt">atomic</span> magnetometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dolgovskiy, V.; Lebedev, V.; Colombo, S.; Weis, A.; Michen, B.; Ackermann-Hirschi, L.; Petri-Fink, A.</p> <p>2015-04-01</p> <p>The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their <span class="hlt">magnetic</span> relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped <span class="hlt">atomic</span> magnetometers can be used to record accurate time series of the relaxing <span class="hlt">magnetic</span> field produced by pre-polarised SPIONs. We have investigated dry in vitro maghemite nanoparticle samples with different size distributions (average radii ranging from 14 to 21 nm) and analysed their relaxation using the Néel-Brown formalism. Fitting our model function to the magnetorelaxation (MRX) data allows us to extract the anisotropy constant K and the saturation magnetisation MS of each sample. While the latter was found not to depend on the particle size, we observe that K is inversely proportional to the (time- and size-) averaged volume of the magnetised particle fraction. We have identified the range of SPION sizes that are best suited for MRX detection considering our specific experimental conditions and sample preparation technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013sf2a.conf..415S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013sf2a.conf..415S"><span id="translatedtitle">The structure of the thermally bistable, turbulent and <span class="hlt">magnetized</span> <span class="hlt">atomic</span> gas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saury, E.; Bracco, A.; Boulanger, F.; Miville-Deschnes, M.-A.; Hennebelle, P.</p> <p>2013-11-01</p> <p>The work presented here is focused on the evolution of the <span class="hlt">atomic</span> and diffuse interstellar medium that provides the initial conditions to the formation of molecular clouds. We quantify the roles of thermal instability, turbulence and <span class="hlt">magnetic</span> field in the formation of CNM gas out of the WNM with numerical simulations performed with the code HERACLES. First, we present the results of a study of the WNM-CNM transition in the non-<span class="hlt">magnetized</span> case. With WNM initial conditions and stirring in of turbulent motions at large scales, the hydrodynamical simulations reproduce basic observational statistics of the diffuse ISM as the mass in the cold phase. A process of compression is needed to create CNM through the thermal instability, either with a majority of compressible modes of the injected turbulent velocity field or with an initial density of the WNM higher than the fiducial value for the thermal equilibrium. Lastly, we present a set of MHD simulations based on the parameter study performed in the hydrodynamical case and compare their ability to create CNM and their properties regarding the dust polarization, as the maps of the stokes parameters and the dispersion of the polarization angle. We obtain a good agreement with the recent results of the Planck satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvE..75c1707L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvE..75c1707L"><span id="translatedtitle">Nuclear <span class="hlt">magnetic</span> resonance parameters of <span class="hlt">atomic</span> xenon dissolved in Gay-Berne model liquid crystal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lintuvuori, Juho; Straka, Michal; Vaara, Juha</p> <p>2007-03-01</p> <p>We present constant-pressure Monte Carlo simulations of nuclear <span class="hlt">magnetic</span> resonance (NMR) spectral parameters, nuclear <span class="hlt">magnetic</span> shielding relative to the free <span class="hlt">atom</span> as well as nuclear quadrupole coupling, for <span class="hlt">atomic</span> xenon dissolved in a model thermotropic liquid crystal. The solvent is described by Gay-Berne (GB) molecules with parametrization κ=4.4 , κ'=20.0 , and μ=ν=1 . The reduced pressure of P⋆=2.0 is used. Previous simulations of a pure GB system with this parametrization have shown that upon lowering the temperature, the model exhibits isotropic, nematic, smectic- A , and smectic- B /molecular crystal phases. We introduce spherical xenon solutes and adjust the energy and length scales of the GB-Xe interaction to those of the GB-GB interaction. This is done through first principles quantum chemical calculations carried out for a dimer of model mesogens as well as the mesogen-xenon complex. We preparametrize quantum chemically the Xe nuclear shielding and quadrupole coupling tensors when interacting with the model mesogen, and use the parametrization in a pairwise additive fashion in the analysis of the simulation. We present the temperature evolution of Xe129/131 shielding and Xe131 quadrupole coupling in the different phases of the GB model. From the simulations, separate isotropic and anisotropic contributions to the experimentally available total shielding can be obtained. At the experimentally relevant concentration, the presence of the xenon <span class="hlt">atoms</span> does not significantly affect the phase behavior as compared to the pure GB model. The simulations reproduce many of the characteristic experimental features of Xe NMR in real thermotropic LCs: Discontinuity in the value or trends of the shielding and quadrupole coupling at the nematic-isotropic and smectic- A -nematic phase transitions, nonlinear shift evolution in the nematic phase reflecting the behavior of the orientational order parameter, and decreasing shift in the smectic- A phase. The last observation is due to the preference of the xenon solutes to occupy the interlayer space where the density of the medium is reduced as compared to the layers. There are systematic deviations, however, in the magnitude of the shielding and its discontinuities, as well as the distribution of the solutes in the translationally ordered smectic- A phase, between the simulation and experiment. These deficiencies are believed to result from the lack of flexibility of the GB model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21352270','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21352270"><span id="translatedtitle">Investigation at the <span class="hlt">atomic</span> scale of the Co spatial distribution in Zn(Co)O <span class="hlt">magnetic</span> semiconductor oxide</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Larde, R.; Talbot, E.; Vurpillot, F.; Pareige, P.; Schmerber, G.; Beaurepaire, E.; Dinia, A.; Pierron-Bohnes, V.</p> <p>2009-06-15</p> <p>A sputtered Zn{sub 0.95}Co{sub 0.05}O layer was chemically analyzed at the <span class="hlt">atomic</span> scale in order to provide an accurate image of the distribution of Co <span class="hlt">atoms</span> in the ZnO matrix. The investigation of the <span class="hlt">magnetic</span> properties shows that the as-deposited Zn{sub 0.95}Co{sub 0.05}O is ferromagnetic at room temperature. <span class="hlt">Atom</span> probe tomography reveals a homogeneous distribution of all chemical species in the layer and the absence of any Co clustering. This result proves that the ferromagnetic properties of this <span class="hlt">magnetic</span> semiconductor cannot be attributed to a secondary phase or to metallic Co precipitates within the layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPJD...69..225A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPJD...69..225A"><span id="translatedtitle">Measurement of a false electric dipole moment signal from 199Hg <span class="hlt">atoms</span> exposed to an inhomogeneous <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Afach, S.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; van der Grinten, M. G. D.; Grujic, Z.; Harris, P. G.; Heil, W.; Hélaine, V.; Henneck, R.; Horras, M.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaïdic, Y.; Kirch, K.; Knowles, P.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Piegsa, F. M.; Pignol, G.; Prashant, P. N.; Quéméner, G.; Rebreyend, D.; Ries, D.; Roccia, S.; Schmidt-Wellenburg, P.; Severijns, N.; Weis, A.; Wursten, E.; Wyszynski, G.; Zejma, J.; Zenner, J.; Zsigmond, G.</p> <p>2015-10-01</p> <p>We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for 199Hg <span class="hlt">atoms</span> contained in a volume permeated with aligned <span class="hlt">magnetic</span> and electric fields. This shift arises from the interplay between the inevitable <span class="hlt">magnetic</span> field gradients and the motional <span class="hlt">magnetic</span> field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron <span class="hlt">magnetic</span> resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied <span class="hlt">magnetic</span> field gradient. Our results are in good agreement with theoretical expectations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=cooling+AND+methods&pg=4&id=EJ484206','ERIC'); return false;" href="http://eric.ed.gov/?q=cooling+AND+methods&pg=4&id=EJ484206"><span id="translatedtitle">Global <span class="hlt">Warming</span>?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Eichman, Julia Christensen; Brown, Jeff A.</p> <p>1994-01-01</p> <p>Presents information and data on an experiment designed to test whether different atmosphere compositions are affected by light and temperature during both cooling and heating. Although flawed, the experiment should help students appreciate the difficulties that researchers face when trying to find evidence of global <span class="hlt">warming</span>. (PR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APLM....3g6102M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APLM....3g6102M"><span id="translatedtitle">A <span class="hlt">magnetic</span> <span class="hlt">atomic</span> laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meshkian, R.; Ingason, A. S.; Arnalds, U. B.; Magnus, F.; Lu, J.; Rosen, J.</p> <p>2015-07-01</p> <p>We present synthesis and characterization of a new <span class="hlt">magnetic</span> <span class="hlt">atomic</span> laminate: (Mo0.5Mn0.5)2GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of ˜530 °C. The films display a <span class="hlt">magnetic</span> response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 μB per metal <span class="hlt">atom</span> (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of <span class="hlt">magnetic</span> laminates based on so called MAX phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342054','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342054"><span id="translatedtitle">Photometric variability in a <span class="hlt">warm</span>, strongly <span class="hlt">magnetic</span> DQ white dwarf, SDSS J103655.39+652252.2</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Williams, Kurtis A.; Winget, D. E.; Montgomery, M. H.; Hermes, J. J.; Falcon, Ross E.; Winget, K. I.; Dufour, Patrick; Kepler, S. O.; Bolte, Michael; Liebert, James E-mail: jamesliebert@gmail.com</p> <p>2013-06-01</p> <p>We present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with an amplitude 0.442% ± 0.024%; no other periodic modulations are observed with amplitudes ≳ 0.13%. The period, amplitude, and phase of this modulation are constant within errors over 16 months. The spectrum of SDSS J1036+6522 shows <span class="hlt">magnetic</span> splitting of carbon lines, and we use Paschen-Back formalism to develop a grid of model atmospheres for mixed carbon and helium atmospheres. Our models, while reliant on several simplistic assumptions, nevertheless match the major spectral and photometric properties of the star with a self-consistent set of parameters: T {sub eff} ≈ 15, 500 K, log g ≈ 9, log (C/He) = –1.0, and a mean <span class="hlt">magnetic</span> field strength of 3.0 ± 0.2 MG. The temperature and abundances strongly suggest that SDSS J1036+6522 is a transition object between the hot, carbon-dominated DQs and the cool, helium-dominated DQs. The variability of SDSS J1036+6522 has characteristics similar to those of the variable hot carbon-atmosphere white dwarfs (DQVs), however, its temperature is significantly cooler. The pulse profile of SDSS J1036+6522 is nearly sinusoidal, in contrast with the significantly asymmetric pulse shapes of the known <span class="hlt">magnetic</span> DQVs. If the variability in SDSS J1036+6522 is due to the same mechanism as other DQVs, then the pulse shape is not a definitive diagnostic on the absence of a strong <span class="hlt">magnetic</span> field in DQVs. It remains unclear whether the root cause of the variability in SDSS J1036+6522 and the other hot DQVs is the same.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1174115','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1174115"><span id="translatedtitle"><span class="hlt">Atomic</span> moments in Mn<sub>2</sub>CoAl thin films analyzed by X-ray <span class="hlt">magnetic</span> circular dichroism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.</p> <p>2014-12-05</p> <p>Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The <span class="hlt">magnetic</span> properties of Mn<sub>2</sub>CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the <span class="hlt">atomic</span>-specific <span class="hlt">magnetic</span> moments of Mn and Co <span class="hlt">atoms</span> measured through X-ray <span class="hlt">magnetic</span> circular dichroism as a function of annealing and the consequent structural ordering. Results indicate that the structural distortion mainly affects the Mn <span class="hlt">atoms</span> as seen by the reduction of the <span class="hlt">magnetic</span> moment from its predicted value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AIPC..771....3R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AIPC..771....3R"><span id="translatedtitle">The Role of <span class="hlt">Atomic</span> and Molecular Processes in <span class="hlt">Magnetic</span> Fusion Plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reiter, Detlev; Baeva, Margarita; Marchuk, Oleksandr; Janev, Ratko K.</p> <p>2005-05-01</p> <p>Plasma edge physics (plasmas with temperatures in the 1 to 100 eV range, near solid surfaces) has become a key issue in controlled nuclear fusion research. As for the physics of the fully ionized hot plasma core, appropriate dimensionless parameters have been identified: present fusion research acts like wind-channel experiments on downsized models, with respect to future fusion reactors. This is not longer possible for the plasma edge region due to dominant effects from <span class="hlt">atomic</span> and surface processes. Integrated computational models comprising the physics of the plasma flow near boundaries, the <span class="hlt">atomic</span> and molecular processes and the particle-surface interactions are the only tool to evaluate present experimental results (LHD, JT60, Tore Supra, JET,…) with respect to their relevance for future fusion power experiments (ITER) or a reactor. In particular proton and electron collisions with the hydrogenic molecules H2, O2, T2, DT, and their ions, play a key role in cooling and attenuating the <span class="hlt">magnetically</span> confined plasma, before it hits exposed target surfaces. The surface released molecules travel in a bath of electrons and hydrogenic ions, with plasma temperatures (in the relevant region) in the 1 to 20 eV range, and typical (plasma) scale lengths are in the 1 to 10 cm range. Sample calculations with current fusion plasma edge codes, as e.g. used by the international design team for the ITER prototypical fusion reactor, applied to the tokamak with the highest divertor collisionality today (Alcator-C-Mod), are used to demonstrate these issues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20718975','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20718975"><span id="translatedtitle">The Role of <span class="hlt">Atomic</span> and Molecular Processes in <span class="hlt">Magnetic</span> Fusion Plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Reiter, Detlev; Baeva, Margarita; Marchuk, Oleksandr; Janev, Ratko K.</p> <p>2005-05-27</p> <p>Plasma edge physics (plasmas with temperatures in the 1 to 100 eV range, near solid surfaces) has become a key issue in controlled nuclear fusion research. As for the physics of the fully ionized hot plasma core, appropriate dimensionless parameters have been identified: present fusion research acts like wind-channel experiments on downsized models, with respect to future fusion reactors. This is not longer possible for the plasma edge region due to dominant effects from <span class="hlt">atomic</span> and surface processes. Integrated computational models comprising the physics of the plasma flow near boundaries, the <span class="hlt">atomic</span> and molecular processes and the particle-surface interactions are the only tool to evaluate present experimental results (LHD, JT60, Tore Supra, JET,...) with respect to their relevance for future fusion power experiments (ITER) or a reactor.In particular proton and electron collisions with the hydrogenic molecules H2, O2, T2, DT, and their ions, play a key role in cooling and attenuating the <span class="hlt">magnetically</span> confined plasma, before it hits exposed target surfaces. The surface released molecules travel in a bath of electrons and hydrogenic ions, with plasma temperatures (in the relevant region) in the 1 to 20 eV range, and typical (plasma) scale lengths are in the 1 to 10 cm range.Sample calculations with current fusion plasma edge codes, as e.g. used by the international design team for the ITER prototypical fusion reactor, applied to the tokamak with the highest divertor collisionality today (Alcator-C-Mod), are used to demonstrate these issues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPlPh..80...89D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPlPh..80...89D"><span id="translatedtitle">Stability of ion acoustic solitary waves in a <span class="hlt">magnetized</span> plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons having vortex-like velocity distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.; Das</p> <p>2014-02-01</p> <p>Schamel's modified Korteweg-de Vries-Zakharov-Kuznetsov (S-ZK) equation, governing the behavior of long wavelength, weak nonlinear ion acoustic waves propagating obliquely to an external uniform static <span class="hlt">magnetic</span> field in a plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons (due to the presence of fast energetic electrons) having vortex-like velocity distribution function (due to the presence of trapped electrons), immersed in a uniform (space-independent) and static (time-independent) <span class="hlt">magnetic</span> field, admits solitary wave solutions having a sech 4 profile. The higher order stability of this solitary wave solution of the S-ZK equation has been analyzed with the help of multiple-scale perturbation expansion method of Allen and Rowlands (Allen, M. A. and Rowlands, G. 1993 J. Plasma Phys. 50, 413; 1995 J. Plasma Phys. 53, 63). The growth rate of instability is obtained correct to the order k 2, where k is the wave number of a long wavelength plane wave perturbation. It is found that the lowest order (at the order k) instability condition is strongly sensitive to the angle of propagation (δ) of the solitary wave with the external uniform static <span class="hlt">magnetic</span> field, whereas at the next order (at the order k 2) the solitary wave solutions of the S-ZK equation are unstable irrespective of δ. It is also found that the growth rate of instability up to the order k 2 for the electrons having Boltzmann distribution is higher than that of the non-thermal electrons having vortex-like distribution for any fixed δ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARC21015D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARC21015D"><span id="translatedtitle">Revealing the <span class="hlt">Atomic</span> Site-Dependent g Factor within a Single <span class="hlt">Magnetic</span> Molecule via the Extended Kondo Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, Shixuan</p> <p></p> <p>Control over charge and spin states at the single molecule level is crucial not only for a fundamental understanding of charge and spin interactions but also represents a prerequisite for development of molecular electronics and spintronics. In this talk, I will talk about the extended spin distribution in space beyond the central Mn ion, and onto the non-<span class="hlt">magnetic</span> constituent <span class="hlt">atoms</span> of the MnPc molecule. This extended spin distribution results in an extended Kondo effect, which can be explained by spin polarization induced by symmetry breaking of the molecular framework, as confirmed by DFT calculations. Measuring the evolution of the Kondo splitting with applied <span class="hlt">magnetic</span> fields at different <span class="hlt">atomic</span> sites, we find a spatial variation of the g-factor within a single molecule for the first time. The existence of <span class="hlt">atomic</span> site-dependent g-factors can be attributed to specific molecular orbitals distributed over the entire molecule. This work not only open up a new opportunity for quantum information recording, but also provide a new route to explore the internal electronic and spin structure of complex molecules, hard to achieve otherwise. (L. W. Liu et al., Phys. Rev. Lett. 2015, 114, 126601. In collaboration with Liwei Liu, Kai Yang, Yuhang Jiang, Li Gao, Qi Liu, Boqun Song, Wende Xiao, Haitao Zhou, Hongjun Gao in CAS, Min Ouyang in MU, and A.H. Castro Neto in SNU.) Revealing the <span class="hlt">Atomic</span> Site-Dependent g Factor within a Single <span class="hlt">Magnetic</span> Molecule via the Extended Kondo Effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005RPPh...68.1343H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005RPPh...68.1343H"><span id="translatedtitle">Global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Houghton, John</p> <p>2005-06-01</p> <p>'Global <span class="hlt">warming</span>' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this <span class="hlt">warming</span> are changes of climate. The basic science of the 'greenhouse effect' that leads to the <span class="hlt">warming</span> is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global <span class="hlt">warming</span> is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JETP..118..687M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JETP..118..687M"><span id="translatedtitle">Selective laser pumping of <span class="hlt">magnetic</span> sublevels in the hyperfine structure of the cesium <span class="hlt">atom</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Magunov, A. I.; Palchikov, V. G.</p> <p>2014-05-01</p> <p>The evolution of the populations of the <span class="hlt">magnetic</span> sublevels of the cesium <span class="hlt">atom</span> (133Cs isotope) in resonant laser fields with linear polarization is analyzed using the equations for the density matrix. Analytic expressions are derived for stationary populations resulting from laser-induced optical transitions on the hyperfine structure components F g = 3 ? F e = 2, 3 and F f = 4 ? F e = 3, 4 of lines D 1 (62 S 1/2 ? 62 P 1/2) and D 2 (62 S 1/2 ? 62 P 3/2) depending on the initial values of the populations. The numerical solution of the evolution equations gives the characteristic times of stabilization of the steady regime as functions of laser field intensities and detuning from optical resonance. We determine the sequences of optical transitions increasing (by more than an order of magnitude) the population of the lower sublevel 62 S 1/2 F g = 3 M = 0 of the "clock" microwave transition F g = 3 M = 0 ? F f = 4 M = 0 in the cesium frequency standard, which increases the signal intensity in the recording system by the same proportion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoTPh..65...57K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoTPh..65...57K"><span id="translatedtitle">Roles of <span class="hlt">Atomic</span> Injection Rate and External <span class="hlt">Magnetic</span> Field on Optical Properties of Elliptical Polarized Probe Light</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karimi, R.; S. H., Asadpour; Batebi, S.; H. Rahimpour, Soleimani</p> <p>2016-01-01</p> <p>In this paper we investigate the optical properties of an open four-level tripod <span class="hlt">atomic</span> system driven by an elliptically polarized probe field in the presence of the external <span class="hlt">magnetic</span> field and compare its properties with the corresponding closed system. Our result reveals that absorption, dispersion and group velocity of probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field, <span class="hlt">magnetic</span> field and cavity parameters i.e. the <span class="hlt">atomic</span> exit rate from cavity and <span class="hlt">atomic</span> injection rates. We show that the system can exhibit multiple electromagnetically induced transparency windows in the presence of the external <span class="hlt">magnetic</span> field. The numerical result shows that the probe field in the open system can be amplified by appropriate choice of cavity parameters, while in the closed system with introduce appropriate phase difference between fields the probe field can be enhanced. Also it is shown that the group velocity of light pulse can be controlled by external <span class="hlt">magnetic</span> field, relative phase of applied fields and cavity parameters. By changing the parameters the group velocity of light pulse changes from subluminal to superluminal light propagation and vice versa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MARJ33001P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MARJ33001P"><span id="translatedtitle">Manipulation of p-wave scattering of cold <span class="hlt">atoms</span> in low dimensions using the <span class="hlt">magnetic</span> field vector</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, Shi-Guo; Tan, Shina; Jiang, Kaijun</p> <p>2014-03-01</p> <p>It is well known that the <span class="hlt">magnetic</span> Feshbach resonances of cold <span class="hlt">atoms</span> are sensitive to the magnitude of the external <span class="hlt">magnetic</span> field. Much less attention has been paid to the direction of such a field. In this work we calculate the scattering properties of spin polarized fermionic <span class="hlt">atoms</span> in reduced dimensions, near a p-wave Feshbach resonance. Because of spatial anisotropy of the p-wave interaction, the scattering has nontrivial dependence on both the magnitude and the direction of the <span class="hlt">magnetic</span> field. In addition, we identify an inelastic scattering process which is impossible in the isotropic-interaction model; the rate of this process depends considerably on the direction of the <span class="hlt">magnetic</span> field. Significantly, an EPR entangled pair of identical fermions may be produced during this inelastic collision. This work opens a new method to manipulate resonant cold <span class="hlt">atomic</span> interactions. CPSF (Grant No. 2012M510187), Special Financial Grant from CPSF (Grant No. 2013T60762), the NSFC projects (Grant No. 11004224 and No.11204355) and the NFRP- China (Grant No. 2011CB921601), NSF (Grant No. PHY-1068511), Alfred P. Sloan Foundation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..385..138J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..385..138J"><span id="translatedtitle"><span class="hlt">Magnetic</span> properties of Mg12O12 nanocage doped with transition metal <span class="hlt">atoms</span> (Mn, Fe, Co and Ni): DFT study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Javan, Masoud Bezi</p> <p>2015-07-01</p> <p>Binding energy of the Mg12O12 nanocage doped with transition metals (TM=Mn, Fe, Co and Ni) in endohedrally, exohedrally and substitutionally forms were studied using density functional theory with the generalized gradient approximation exchange-correlation functional along 6 different paths inside and outside of the Mg12O12 nanocage. The most stable structures were determined with full geometry optimization near the minimum of the binding energy curves of all the examined paths inside and outside of the Mg12O12 nanocage. The results reveal that for all stable structures, the Ni <span class="hlt">atom</span> has a larger binding energy than the other TM <span class="hlt">atoms</span>. It is also found that for all complexes additional peaks contributed by TM-3d, 4s and 4p states appear in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gap of the host MgO cluster. The mid-gap states are mainly due to the hybridization between TM-3d, 4s and 4p orbitals and the cage π orbitals. The <span class="hlt">magnetic</span> moment of the endohedrally doped TM <span class="hlt">atoms</span> in the Mg12O12 are preserved to some extent due to the interaction between the TM and Mg12O12 nanocage, in contrast to the completely quenched <span class="hlt">magnetic</span> moment of the Fe and Ni <span class="hlt">atoms</span> in the Mg11(TM)O12 complexes. Furthermore, charge population analysis shows that charge transfer occurs from TM <span class="hlt">atom</span> to the cage for endohedrally and substitutionally doping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/40276848','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/40276848"><span id="translatedtitle">Dynamic, self-assembled aggregates of <span class="hlt">magnetized</span>, millimeter-sized objects rotating at the liquid-air interface: Macroscopic, two-dimensional classical artificial <span class="hlt">atoms</span> and molecules</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grzybowski, Bartosz A.; Jiang, Xingyu; Stone, Howard A.; Whitesides, George M.</p> <p>2001-07-01</p> <p>This paper describes self-assembly of millimeter-sized, <span class="hlt">magnetized</span> disks floating on a liquid-air interface, and rotating under the influence of a rotating external <span class="hlt">magnetic</span> field. Spinning of the disks results in hydrodynamic repulsion between them, while the rotating <span class="hlt">magnetic</span> field produces an average confining potential acting on all disks. The interplay between hydrodynamic and <span class="hlt">magnetic</span> interactions leads to the formation of patterns. Theoretical analysis of hydrodynamic and <span class="hlt">magnetic</span> forces indicates that the interactions in this system are similar to those acting in systems of finite numbers of particles behaving classically (''classical artificial <span class="hlt">atoms</span>''). Macroscopic artificial <span class="hlt">atoms</span> and molecules are described, and the rules governing their morphologies outlined.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyE...80..142S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyE...80..142S"><span id="translatedtitle">Electronic and <span class="hlt">magnetic</span> behaviors of graphene with 5d series transition metal <span class="hlt">atom</span> substitutions: A first-principles study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Minglei; Tang, Wencheng; Ren, Qingqiang; Zhao, Yiming; Wang, Sake; Yu, Jin; Du, Yanhui; Hao, Yitong</p> <p>2016-06-01</p> <p>The electronic structures and <span class="hlt">magnetic</span> behaviors of graphene with 5d series transition metal <span class="hlt">atom</span> substitutions are investigated by performing first-principles calculations. All the impurities are tightly bonded to single vacancy in a graphene sheet. The substitutions of La and Ta lead to Fermi level shifting to valence and conduction band, respectively. Both the two substitutions result in metallic properties. Moreover, the Hf, Os and Pt-substituted systems exhibit semiconductor properties, while the Re and Ir-substituted ones exhibit robust half-metallic properties. Interestingly, W-substituted system shows dilute <span class="hlt">magnetic</span> semiconductor property. On the other hand, the substitution of Ta, W, Re and Ir induce 0.86 μB, 2 μB, 1 μB and 0.99 μB <span class="hlt">magnetic</span> moment, respectively. Our studies demonstrate that the 5d series transition metal substituted graphene have potential applications in nanoelectronics, spintronics and <span class="hlt">magnetic</span> storage devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhB...49f5006F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhB...49f5006F"><span id="translatedtitle">Low frequency <span class="hlt">magnetic</span> field suppression in an <span class="hlt">atomic</span> spin co-magnetometer with a large electron <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Jiancheng; Chen, Yao; Zou, Sheng; Liu, Xuejing; Hu, Zhaohui; Quan, Wei; Yuan, Heng; Ding, Ming</p> <p>2016-03-01</p> <p>In a K-Rb-21Ne co-magnetometer, the Rb electron <span class="hlt">magnetic</span> field which is experienced by the nuclear spin is about 100 times larger than that of the K in a K-3He co-magnetometer. The large electron <span class="hlt">magnetic</span> field which is neglected in the K-3He co-magnetometer coupled Bloch equations model is considered here in the K-Rb-21Ne co-magnetometer to study the low frequency <span class="hlt">magnetic</span> field suppression effect. Theoretical analysis and experimental results shows that in the K-Rb-21Ne spin co-magnetometer, not only the nuclear spin but also the large electron spin <span class="hlt">magnetic</span> field compensate the external <span class="hlt">magnetic</span> field noise. By comparison, only the 3He nuclear spins mainly compensate the external <span class="hlt">magnetic</span> field noise in a K-3He co-magnetometer. With this study, in addition to just increasing the <span class="hlt">magnetic</span> field of the nuclear spins, we can suppress the <span class="hlt">magnetic</span> field noise by increasing the density of the electron spin. We also studied how the <span class="hlt">magnetic</span> field suppression effect relates to the scale factor of the K-Rb-21Ne co-magnetometer and we compared the scale factor with that of the K-3He co-magnetometer. Lastly, we show the sensitivity of our co-magnetometer. The <span class="hlt">magnetic</span> field noise, the air density fluctuation noise and pumping power optimization are studied to improve the sensitivity of the co-magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22299801','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22299801"><span id="translatedtitle">Circuit-quantum electrodynamics with direct <span class="hlt">magnetic</span> coupling to single-<span class="hlt">atom</span> spin qubits in isotopically enriched {sup 28}Si</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tosi, Guilherme Mohiyaddin, Fahd A.; Morello, Andrea; Huebl, Hans</p> <p>2014-08-15</p> <p>Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single <span class="hlt">atoms</span> in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator <span class="hlt">magnetic</span> vacuum field. By using resonators modified to increase the vacuum <span class="hlt">magnetic</span> field at the qubit location, and isotopically purified {sup 28}Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvE..93e3201F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvE..93e3201F"><span id="translatedtitle">Hydrogen <span class="hlt">atom</span> in a quantum plasma environment under the influence of Aharonov-Bohm flux and electric and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falaye, Babatunde James; Sun, Guo-Hua; Silva-Ortigoza, Ramón; Dong, Shi-Hai</p> <p>2016-05-01</p> <p>This study presents the confinement influences of Aharonov-Bohm (AB) flux and electric and <span class="hlt">magnetic</span> fields directed along the z axis and encircled by quantum plasmas on the hydrogen <span class="hlt">atom</span>. The all-inclusive effects result in a strongly attractive system while the localizations of quantum levels change and the eigenvalues decrease. We find that the combined effect of the fields is stronger than a solitary effect and consequently there is a substantial shift in the bound state energy of the system. We also find that to perpetuate a low-energy medium for the hydrogen <span class="hlt">atom</span> in quantum plasmas, a strong electric field and weak <span class="hlt">magnetic</span> field are required, whereas the AB flux field can be used as a regulator. The application of the perturbation technique utilized in this paper is not restricted to plasma physics; it can also be applied in molecular physics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhSS...53.1353Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhSS...53.1353Z"><span id="translatedtitle">Effect of doping by boron, carbon, and nitrogen <span class="hlt">atoms</span> on the <span class="hlt">magnetic</span> and photocatalytic properties of anatase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zainullina, V. M.; Zhukov, V. P.; Korotin, M. A.; Polyakov, E. V.</p> <p>2011-07-01</p> <p>The effect of doping of titanium dioxide with the anatase structure by boron, carbon, and nitrogen <span class="hlt">atoms</span> on the <span class="hlt">magnetic</span> and optical properties and the electronic spectrum of this compound has been investigated using the ab initio tight-binding linear muffin-tin orbital (TB-LMTO) band-structure method in the local spin density approximation explicitly including Coulomb correlations (LSDA + U) in combination with the semiempirical extended Hückel theory (EHT) method. The LSDA + U calculations of the electronic structure, the imaginary part of the dielectric function, the total <span class="hlt">magnetic</span> moments, and the <span class="hlt">magnetic</span> moments at the impurity <span class="hlt">atoms</span> have been carried out. The diagrams of the molecular orbitals of the clusters Ti3 X ( X = B, C, N) have been calculated and the pseudo-space images of the molecular orbitals of the clusters have been constructed. The effect of doping on the nature and origin of photocatalytic activity in the visible spectral range and the specific features of the generation of ferromagnetic interactions in doped anatase have been discussed based on the analysis of the obtained data. It has been shown that, in the sequence TiO2 - y N y → TiO2 - y C y → TiO2 - y B y ( y = 1/16), the photocatalytic activity can increase with the generation of electronic excitations with the participation of impurity bands. The calculated <span class="hlt">magnetic</span> moments for boron and nitrogen <span class="hlt">atoms</span> are equal to 1 μB, whereas the impurity carbon <span class="hlt">atoms</span> are nonmagnetic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790016567&hterms=magnetic+shielding+material&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetic%2Bshielding%2Bmaterial','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790016567&hterms=magnetic+shielding+material&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetic%2Bshielding%2Bmaterial"><span id="translatedtitle">Shielding of longitudinal <span class="hlt">magnetic</span> fields with thin, closely, spaced concentric cylindrical shells with applications to <span class="hlt">atomic</span> clocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wolf, S. A.; Gubser, D. U.; Cox, J. E.</p> <p>1978-01-01</p> <p>A general formula is given for the longitudinal shielding effectiveness of N closed concentric cylinders. The use of these equations is demonstrated by application to the design of <span class="hlt">magnetic</span> shields for hydrogen maser <span class="hlt">atomic</span> clocks. Examples of design tradeoffs such as size, weight, and material thickness are discussed. Experimental results on three sets of shields fabricated by three manufacturers are presented. Two of the sets were designed employing the techniques described. Agreement between the experimental results and the design calculations is then demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvA..92f2701T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvA..92f2701T"><span id="translatedtitle">Ultracold <span class="hlt">magnetically</span> tunable interactions without radiative-charge-transfer losses between Ca+, Sr+, Ba+, and Yb+ ions and Cr <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomza, Michał</p> <p>2015-12-01</p> <p>The Ca+, Sr+, Ba+, and Yb+ ions immersed in an ultracold gas of the Cr <span class="hlt">atoms</span> are proposed as experimentally feasible heteronuclear systems in which ion-<span class="hlt">atom</span> interactions at ultralow temperatures can be controlled with <span class="hlt">magnetically</span> tunable Feshbach resonances without charge transfer and radiative losses. Ab initio techniques are applied to investigate electronic-ground-state properties of the (CaCr)+, (SrCr)+, (BaCr)+, and (YbCr)+ molecular ions. The potential energy curves, permanent electric dipole moments, and static electric dipole polarizabilities are computed. The spin-restricted open-shell coupled-cluster method restricted to single, double, and noniterative triple excitations and the multireference configuration-interaction method restricted to single and double excitations are employed. The scalar relativistic effects are included within the small-core energy-consistent pseudopotentials. The leading long-range induction and dispersion interaction coefficients are also reported. Finally, <span class="hlt">magnetic</span> Feshbach resonances between the Ca+, Sr+, Ba+, and Yb+ ions interacting with the Cr <span class="hlt">atoms</span> are analyzed. The present proposal opens the way towards robust quantum simulations and computations with ultracold ion-<span class="hlt">atom</span> systems free of radiative charge-transfer losses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6743294','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6743294"><span id="translatedtitle"><span class="hlt">Atomization</span> characteristics and direct determination of manganese and magnesium in biological samples using a <span class="hlt">magnetically</span> altered thin-film plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brewer, S.W. Jr.; Sacks, R.D.</p> <p>1988-09-01</p> <p>A <span class="hlt">magnetic</span> field with peak value of 3.7 kG is used to improve the <span class="hlt">atomization</span> characteristics of an electrically vaporized thin-film plasma for the direct determination of Mg and Mn in solid biological materials. Plasmas are generated by high-current capacitive discharges through 350-..mu..g Ag or Au thin films formed on polypropylene substrates. Radiation intensity vs time plots are compared with and without the <span class="hlt">magnetic</span> field for the NBS materials bovine liver, oyster tissue, orchard leaves, citrus leaves, tomato leaves, and pine needles. Analytical standard for Mg are prepared from suspensions of MgO powder, and standards for Mn are prepared from aqueous solutions of Mn(NO/sub 3/)/sub 2/ or MnSO/sub 4/. Analytical accuracy usually is improved with the presence of the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25524662','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25524662"><span id="translatedtitle">Reversible switching of <span class="hlt">magnetic</span> states by electric fields in nitrogenized-divacancies graphene decorated by tungsten <span class="hlt">atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ge, Gui-Xian; Sun, Hai-Bin; Sun, Hai-Bing; Han, Yan; Song, Feng-Qi; Zhao, Ji-Jun; Wang, Guang-Hou; Wan, Jian-Guo</p> <p>2014-01-01</p> <p><span class="hlt">Magnetic</span> graphene-based materials have shown great potential for developing high-performance electronic devices at sub-nanometer such as spintronic data storage units. However, a significant reduction of power consumption and great improvement of structural stability are needed before they can be used for actual applications. Based on the first-principles calculations, here we demonstrate that the interaction between tungsten <span class="hlt">atoms</span> and nitrogenized-divacancies (NDVs) in the hybrid W@NDV-graphene can lead to high stability and large <span class="hlt">magnetic</span> anisotropy energy (MAE). More importantly, reversible switching between different <span class="hlt">magnetic</span> states can be implemented by tuning the MAE under different electric fields, and very low energy is consumed during the switching. Such controllable switching of <span class="hlt">magnetic</span> states is ascribed to the competition between the tensile stain and orbital <span class="hlt">magnetic</span> anisotropy, which originates from the change in the occupation number of W-5d orbitals under the electric fields. Our results provide a promising avenue for developing high-density <span class="hlt">magnetic</span> storage units or multi-state logical switching devices with ultralow power at sub-nanometer. PMID:25524662</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.497a2006S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.497a2006S"><span id="translatedtitle">Magneto-optical effects and rf <span class="hlt">magnetic</span> field detection in cold rubidium <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sycz, Krystian; Wojciechowski, Adam M.; Gawlik, Wojciech</p> <p>2014-04-01</p> <p>We present the results of our latest experiments on <span class="hlt">atomic</span> coherences in cold <span class="hlt">atoms</span>. Interaction of <span class="hlt">atoms</span> with a near-resonant, linearly polarized light leads to an effective creation of long-lived ground-state Zeeman coherences which is observed through the nonlinear Faraday effect or free induction decay signals of the Larmor precession. Both optically and radio-frequency induced Zeeman coherences are observed, with relaxation rates around a 100 Hz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhRvB..5511422H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhRvB..5511422H"><span id="translatedtitle">Thickness dependence of the total <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> in the Cu/Ni/Cu/Si(001) system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hope, S.; Lee, J.; Rosenbusch, P.; Lauhoff, G.; Bland, J. A. C.; Ercole, A.; Bucknall, D.; Penfold, J.; Lauter, H. J.; Lauter, V.; Cubitt, R.</p> <p>1997-05-01</p> <p>Systematic measurements of the <span class="hlt">magnetic</span> moment per Ni <span class="hlt">atom</span> in Cu/Ni/Cu/Si(001) structures have been made using polarized neutron reflection (PNR) for Ni thicknesses in the range 30 <t<400 at room temperature. We find a dramatic reduction in the <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> for t<100 and near bulk values above 100 . These results are corroborated by alternating gradient magnetometer measurements on the same samples. A Cu/Ni-wedge/Cu/Si(001) structure with 30 <t<150 was studied using <span class="hlt">magnetic</span> circular x-ray dichroism (MCXD), polar magneto-optical Kerr effect (MOKE), and reflection high-energy electron diffraction (RHEED) in order to estimate the variation in the values of <Lz>, <Sz>, perpendicular anisotropy strength, and surface in-plane Ni lattice constant, respectively, during epitaxial growth. RHEED measurements show that the in-plane lattice constant falls by 1.7% in the Ni thickness range 30 <t<90 . The MCXD measurements reveal the same trend for <Lz>, <Sz>, and total moment per <span class="hlt">atom</span> versus Ni thickness as found for the total moment by PNR. Polar MOKE measurements confirmed the transition from a perpendicular easy axis towards an in-plane <span class="hlt">magnetic</span> easy axis as has already been extensively studied in the literature. Comparison of the PNR results with RHEED measurements reveal a striking correlation between the increase of in-plane strain and reduction in <span class="hlt">magnetic</span> moment per <span class="hlt">atom</span> with decreasing Ni thickness. While a direct strain-induced variation of the moment based on bulk phase calculations cannot account for the magnitude of the moment variations we observe, we show that the results cannot be attributed to sample contamination, interdiffusion, or a reduction of the Curie temperature with decreasing Ni thickness. Furthermore, the presence of a <span class="hlt">magnetically</span> dead layer in the samples is not consistent with the PNR results. The strong moment variation partially explains the large thickness range for which perpendicular anisotropy is observed in this system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23618196','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23618196"><span id="translatedtitle">Automated <span class="hlt">magnetic</span> sorbent extraction based on octadecylsilane functionalized maghemite <span class="hlt">magnetic</span> particles in a sequential injection system coupled with electrothermal <span class="hlt">atomic</span> absorption spectrometry for metal determination.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Giakisikli, Georgia; Anthemidis, Aristidis N</p> <p>2013-06-15</p> <p>A new automatic sequential injection (SI) system for on-line <span class="hlt">magnetic</span> sorbent extraction coupled with electrothermal <span class="hlt">atomic</span> absorption spectrometry (ETAAS) has been successfully developed for metal determination. In this work, we reported effective on-line immobilization of <span class="hlt">magnetic</span> silica particles into a microcolumn by the external force of two strong neodymium iron boron (NdFeB) <span class="hlt">magnets</span> across it, avoiding the use of frits. Octadecylsilane functionalized maghemite <span class="hlt">magnetic</span> particles were used as sorbent material. The potentials of the system were demonstrated for trace cadmium determination in water samples. The method was based on the on-line complex formation with diethyldithiocarbamate (DDTC), retention of Cd-DDTC on the surface of the MPs and elution with isobutyl methyl ketone (IBMK). The formation mechanism of the <span class="hlt">magnetic</span> solid phase packed column and all critical parameters (chemical, flow, graphite furnace) influencing the performance of the system were optimized and offered good analytical characteristics. For 5 mL sample volume, a detection limit of 3 ng L(-1), a relative standard deviation of 3.9% at 50 ng L(-1) level (n=11) and a linear range of 9-350 ng L(-1) were obtained. The column remained stable for more than 600 cycles keeping the cost down in routine analysis. The proposed method was evaluated by analyzing certified reference materials and natural waters. PMID:23618196</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=atomic+AND+structure&pg=3&id=EJ1040109','ERIC'); return false;" href="http://eric.ed.gov/?q=atomic+AND+structure&pg=3&id=EJ1040109"><span id="translatedtitle">A Simple Demonstration of <span class="hlt">Atomic</span> and Molecular Orbitals Using Circular <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chakraborty, Maharudra; Mukhopadhyay, Subrata; Das, Ranendu Sekhar</p> <p>2014-01-01</p> <p>A quite simple and inexpensive technique is described here to represent the approximate shapes of <span class="hlt">atomic</span> orbitals and the molecular orbitals formed by them following the principles of the linear combination of <span class="hlt">atomic</span> orbitals (LCAO) method. Molecular orbitals of a few simple molecules can also be pictorially represented. Instructors can employ the…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Atomic+AND+structure&pg=4&id=EJ1040109','ERIC'); return false;" href="http://eric.ed.gov/?q=Atomic+AND+structure&pg=4&id=EJ1040109"><span id="translatedtitle">A Simple Demonstration of <span class="hlt">Atomic</span> and Molecular Orbitals Using Circular <span class="hlt">Magnets</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chakraborty, Maharudra; Mukhopadhyay, Subrata; Das, Ranendu Sekhar</p> <p>2014-01-01</p> <p>A quite simple and inexpensive technique is described here to represent the approximate shapes of <span class="hlt">atomic</span> orbitals and the molecular orbitals formed by them following the principles of the linear combination of <span class="hlt">atomic</span> orbitals (LCAO) method. Molecular orbitals of a few simple molecules can also be pictorially represented. Instructors can employ the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhRvA..78c2515E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhRvA..78c2515E"><span id="translatedtitle">Hartree-Fock-Roothaan calculations for many-electron <span class="hlt">atoms</span> and ions in neutron-star <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engel, Dirk; Wunner, Günter</p> <p>2008-09-01</p> <p>The quantitative analysis of the electromagnetic spectra of isolated neutron stars by means of model atmosphere calculations requires extensive data sets of <span class="hlt">atomic</span> energy values and transition probabilities in intense <span class="hlt">magnetic</span> fields. We present a method for the fast computation of wave functions, energies, and oscillator strengths of medium- Z <span class="hlt">atoms</span> and ions at neutron star <span class="hlt">magnetic</span> field strengths B≳107T which strikes a balance between numerical accuracy and computing times. We use a Hartree-Fock ansatz in which each single-electron orbital is expanded in terms of Landau states with one longitudinal expansion function, and each Landau level contributes with a different weight to the orbital. Both the longitudinal expansion functions and the Landau weights are determined in a doubly self-consistent way. Hartree-Fock equations are solved by decomposing the z axis in finite elements and expanding the longitudinal wave functions in terms of sixth-order B -splines. The contributions of the eight lowest Landau levels are taken into account. The procedure can be efficiently parallelized. Results are presented for the ground states and different excited states of <span class="hlt">atoms</span> and ions for nuclear charges Z=2,…,26 and N=2,…,26 electrons, and for oscillator strengths. Wherever possible, a comparison with the results of previous calculations is made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JPlPh..73..869D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JPlPh..73..869D"><span id="translatedtitle">Alternative ion-acoustic solitary waves in <span class="hlt">magnetized</span> plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons having vortex-like velocity distribution: existence and stability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.</p> <p>2007-12-01</p> <p>The solitary structures of the ion-acoustic waves have been considered in a plasma consisting of <span class="hlt">warm</span> adiabatic ions and non-thermal electrons (due to the presence of fast energetic electrons) having a vortex-like velocity distribution function (due to the presence of trapped electrons), immersed in a uniform (space-independent) and static (time-independent) <span class="hlt">magnetic</span> field. The nonlinear dynamics of ion-acoustic waves in such a plasma is governed by the Schamel's modified Korteweg-de Vries-Zakharov-Kuznetsov (S-ZK) equation. This equation admits solitary wave solutions having a profile sech4. When the coefficient of the nonlinear term of this equation vanishes, the vortex-like velocity distribution function of electrons simply becomes the non-thermal velocity distribution function of electrons and the nonlinear behaviour of the same ion-acoustic wave is described by a Korteweg-de Vries-Zakharov-Kuznetsov (KdV-ZK) equation. This equation admits solitary wave solutions having a profile sech2. A combined S-KdV-ZK equation more efficiently describes the nonlinear behaviour of an ion-acoustic wave when the vortex-like velocity distribution function of electrons approaches the non-thermal velocity distribution function of electrons, i.e. when the contribution of trapped electrons tends to zero. This combined S-KdV-ZK equation admits an alternative solitary wave solution having a profile different from either sech4 or sech2. The condition for the existence of this alternative solitary wave solution has been derived. It is found that this alternative solitary wave solution approaches the solitary wave solution (the sech2 profile) of the KdV-ZK equation when the contribution of trapped electrons tends to zero. The three-dimensional stability of these solitary waves propagating obliquely to the external uniform and static <span class="hlt">magnetic</span> field has been investigated by the multiple-scale perturbation expansion method of Allen and Rowlands. The instability condition and the growth rate of the instability have been derived at the lowest order. It is also found that the instability condition and growth rate of instability of the alternative solitary waves are exactly the same as those of the solitary waves as determined from the KdV-ZK equation (the sech2 profile) when the contribution of trapped electrons tends to zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22271318','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22271318"><span id="translatedtitle">Effects of the interplay between <span class="hlt">atomic</span> and <span class="hlt">magnetic</span> order on the properties of metamagnetic Ni-Co-Mn-Ga shape memory alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Seguí, C.</p> <p>2014-03-21</p> <p>Ni-Co-Mn-Ga ferromagnetic shape memory alloys show metamagnetic behavior for a range of Co contents. The temperatures of the structural and <span class="hlt">magnetic</span> transitions depend strongly on composition and <span class="hlt">atomic</span> order degree, in such a way that combined composition and thermal treatment allows obtaining martensitic transformation between any <span class="hlt">magnetic</span> state of austenite and martensite. This work presents a detailed analysis of the effect of <span class="hlt">atomic</span> order on Ni-Co-Mn-Ga alloys through the evolution of structural and <span class="hlt">magnetic</span> transitions after quench from high temperatures and during post-quest ageing. It is found that the way in which the <span class="hlt">atomic</span> order affects the martensitic transformation temperatures and entropy depends on the <span class="hlt">magnetic</span> order of austenite and martensite. The results can be explained assuming that improvement of <span class="hlt">atomic</span> order decreases the free energy of the structural phases according to their <span class="hlt">magnetic</span> order. However, it is assumed in this work that changes in the slope—that is, the entropy—of the Gibbs free energy curves are also decisive to the stability of the two-phase system. The experimental transformation entropy values have been compared with a phenomenological model, based on a Bragg–Williams approximation, accounting for the <span class="hlt">magnetic</span> contribution. The excellent agreement obtained corroborates the <span class="hlt">magnetic</span> origin of changes in transformation entropy brought about by <span class="hlt">atomic</span> ordering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22066282','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22066282"><span id="translatedtitle"><span class="hlt">Magnetic</span> transport apparatus for the production of ultracold <span class="hlt">atomic</span> gases in the vicinity of a dielectric surface</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haendel, S.; Marchant, A. L.; Wiles, T. P.; Hopkins, S. A.; Cornish, S. L.</p> <p>2012-01-15</p> <p>We present an apparatus designed for studies of <span class="hlt">atom</span>-surface interactions using quantum degenerate gases of {sup 85}Rb and {sup 87}Rb in the vicinity of a room temperature dielectric surface. The surface to be investigated is a super-polished face of a glass Dove prism mounted in a glass cell under ultra-high vacuum. To maintain excellent optical access to the region surrounding the surface, <span class="hlt">magnetic</span> transport is used to deliver ultracold <span class="hlt">atoms</span> from a separate vacuum chamber housing the magneto-optical trap (MOT). We present a detailed description of the vacuum apparatus highlighting the novel design features; a low profile MOT chamber and the inclusion of an obstacle in the transport path. We report the characterization and optimization of the <span class="hlt">magnetic</span> transport around the obstacle, achieving transport efficiencies of 70% with negligible heating. Finally, we demonstrate the loading of a hybrid optical-<span class="hlt">magnetic</span> trap with {sup 87}Rb and the creation of Bose-Einstein condensates via forced evaporative cooling close to the dielectric surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110014745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110014745"><span id="translatedtitle"><span class="hlt">Atom</span> Skimmers and <span class="hlt">Atom</span> Lasers Utilizing Them</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.</p> <p>2005-01-01</p> <p><span class="hlt">Atom</span> skimmers are devices that act as low-pass velocity filters for <span class="hlt">atoms</span> in thermal <span class="hlt">atomic</span> beams. An <span class="hlt">atom</span> skimmer operating in conjunction with a suitable thermal <span class="hlt">atomic</span>-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow <span class="hlt">atoms</span> for a magneto-optical trap or other apparatus in an <span class="hlt">atomic</span>-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of <span class="hlt">atomic</span> gases, spectra of trapped <span class="hlt">atoms</span>, and collisions of slowly moving <span class="hlt">atoms</span>. An <span class="hlt">atom</span> skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal <span class="hlt">atomic</span>-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity <span class="hlt">atoms</span> are to be used. Permanent rare-earth <span class="hlt">magnets</span> are placed around the tube in a yoke of high-<span class="hlt">magnetic</span>-permeability material to establish a quadrupole or octupole <span class="hlt">magnetic</span> field leading from the source to the trap. The <span class="hlt">atoms</span> are attracted to the locus of minimum <span class="hlt">magnetic</span>-field intensity in the middle of the tube, and the gradient of the <span class="hlt">magnetic</span> field provides centripetal force that guides the <span class="hlt">atoms</span> around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the <span class="hlt">magnetic</span> field and the radius of curvature of the tube. <span class="hlt">Atoms</span> moving at lesser velocities are successfully guided; faster <span class="hlt">atoms</span> strike the tube wall and are lost from the beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PPNL...10..119S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PPNL...10..119S"><span id="translatedtitle">High Z effects in accounting for radiative component of the electron <span class="hlt">magnetic</span> moment in hydrogen-like <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sveshnikov, K. A.; Khomovskii, D. I.</p> <p>2013-03-01</p> <p>The behavior of electron energy levels in hydrogen-like <span class="hlt">atoms</span> is studied while taking into account the nonperturbative interaction between the radiative component of the <span class="hlt">magnetic</span> moment of a free electron Δ g free and the Coulomb field of an <span class="hlt">atomic</span> nucleus with charge Z, including those with Z > 137. It is shown that for Zα ≪ 1 the energy-level shift is rather effectively determined through the matrix elements of the corresponding Dirac-Pauli operator with relativistic Coulomb wave functions. At the same time, for superheavy nuclei with Z ˜ 170, this shift, generated by Δ g free, is genuinely nonperturbative, behaves like ˜ Z 5 near the threshold of negative continuum, exceeds all the estimates of radiative corrections coming from vacuum polarization and electron self-energy known so far, and turns out to be at least of the same order as the effects of nuclear charge screening by filled electron shells.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20718205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20718205"><span id="translatedtitle">Splitting of an electromagnetically induced transparency window of rubidium <span class="hlt">atoms</span> in a static <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wei Xiaogang; Wu Jinhui; Sun Guixia; Shao Zhuang; Kang Zhihui; Jiang Yun; Gao Jinyue</p> <p>2005-08-15</p> <p>We study the phenomenon of electromagnetically induced transparency (EIT) of {sup 87}Rb vapor at the temperature of 325 K in a <span class="hlt">magnetic</span> field. Two linearly polarized orthogonal laser fields act on two dipole-allowed transitions of the D1 line of {sup 87}Rb in the {lambda} configuration, respectively. In the absence of <span class="hlt">magnetic</span> fields, we observe a wide EIT window with the contrast of about 66% while when the <span class="hlt">magnetic</span> field is applied, the wide EIT window is split into three or four narrower subwindows with contrasts of 32% or 16% due to the lifting of <span class="hlt">magnetic</span> sublevels' degeneracy. The number of EIT subwindows depends on the <span class="hlt">magnetic</span> field orientation. Our theoretical simulations and analysis are in good agreement with the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093418','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093418"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field effects in transitions of X Li molecules (X: even isotopes of group II <span class="hlt">atoms</span>)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gopakumar, Geetha; Abe, Minori; Hada, Masahiko; Kajita, Masatoshi</p> <p>2011-10-15</p> <p>We analyze the Zeeman shift in the (v,N)=(0,0){yields}(1,0) transition frequency of X Li molecules (X: even isotopes of group II <span class="hlt">atoms</span>), which is of interest in metrology. The Zeeman shift in the transition frequency between stretching states is found to be less than 1 mHz with a <span class="hlt">magnetic</span> field of 1 G. X {sup 6}Li molecules are more advantageous than X {sup 7}Li molecules for measuring the transition frequency without the Zeeman shift because of the smaller g factor of the Li nuclear spin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20951200','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20951200"><span id="translatedtitle"><span class="hlt">Atom</span> Interferometer Based on Phase Coherent Splitting of Bose-Einstein Condensates with an Integrated <span class="hlt">Magnetic</span> Grating</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guenther, A.; Kraft, S.; Zimmermann, C.; Fortagh, J.</p> <p>2007-04-06</p> <p>We report the phase coherent splitting of Bose-Einstein condensates by means of a phase grating produced near the surface of a microelectronic chip. A lattice potential with a period of 4 {mu}m is generated by the superposition of static and oscillating <span class="hlt">magnetic</span> fields. Precise control of the diffraction is achieved by controlling the currents in the integrated conductors. The interference of overlapping diffraction orders is observed after 8 ms of propagation in a harmonic trap and subsequent ballistic expansion of the <span class="hlt">atomic</span> ensemble. By analyzing the interference pattern we show a reproducible phase relation between the diffraction orders with an uncertainty limited by the resolution of the diffraction grating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AIPC..899...34G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AIPC..899...34G"><span id="translatedtitle">Coherent <span class="hlt">Atom</span> Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D <span class="hlt">Magnetized</span> Reflection Gratings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Bocvarski, V.; Ducloy, M.</p> <p>2007-04-01</p> <p>1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static <span class="hlt">magnetic</span> field, are used to study 1D and 2D diffraction of fast metastable helium <span class="hlt">atoms</span> He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27063394','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27063394"><span id="translatedtitle">Electric field control of the <span class="hlt">magnetic</span> anisotropy energy of double-vacancy graphene decorated by iridium <span class="hlt">atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ge, Gui-Xian; Li, Ying-Bin; Wang, Guang-Hou; Wan, Jian-Guo</p> <p>2016-04-20</p> <p>To solve the fundamental dilemma in data storage applications, it is crucial to manipulate the <span class="hlt">magnetic</span> anisotropy energy (MAE). Herein, using first-principles calculations, we predict that the system of double-vacancy graphene decorated by iridium <span class="hlt">atoms</span> possesses high stability, giant MAE, perpendicular-anisotropy and long-range ferromagnetic coupling. More importantly, the amplitude of MAE can be manipulated by electric fields. This is due to the change in the occupation number of Ir-5d orbitals. The present hybrid system could be a high-performance nanoscale information storage device with ultralow energy consumption. PMID:27063394</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6881570','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6881570"><span id="translatedtitle">Direct <span class="hlt">atomic</span> emission determination of some trace metals in solid powder samples with a <span class="hlt">magnetically</span> tailored capacitive discharge plasma</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Albers, D.; Sacks, R.</p> <p>1987-02-15</p> <p>A <span class="hlt">magnetic</span> field is used to alter the structure of the plasma produced by the electrical vaporization of a 40 nm thick, 350 ..mu..g silver film. The films are vacuum deposited on plastic substrates. The sample, as a particle suspension in isopropyl alcohol, is applied to the film surface and vaporized along with the film by interaction with the hot plasma gases. A <span class="hlt">magnetic</span> field of a few kilogauss results in a significant drift motion of the plasma. This reduces the rate of plasma expansion, improves positional stability, and dramatically increases the rate of sample <span class="hlt">atomization</span>. In addition, continuum background radiation is more localized near the substrate surface, and increased line-to-background ratios are obtained if this region is masked. General analytical features of the plasma are discussed and analytical data presented for several NBS solid powder reference materials. Relative errors typically are in the 5-10% range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19256651','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19256651"><span id="translatedtitle">Development of <span class="hlt">atomic</span> force microscope with wide-band <span class="hlt">magnetic</span> excitation for study of soft matter dynamics.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kageshima, Masami; Chikamoto, Takuma; Ogawa, Tatsuya; Hirata, Yoshiki; Inoue, Takahito; Naitoh, Yoshitaka; Li, Yan Jun; Sugawara, Yasuhiro</p> <p>2009-02-01</p> <p>In order to probe dynamical properties of mesoscopic soft matter systems such as polymers, structured liquid, etc., a new <span class="hlt">atomic</span> force microscopy apparatus with a wide-band <span class="hlt">magnetic</span> cantilever excitation system was developed. Constant-current driving of an electromagnet up to 1 MHz was implemented with a closed-loop driver circuit. Transfer function of a commercial cantilever attached with a <span class="hlt">magnetic</span> particle was measured in a frequency range of 1-1000 kHz in distilled water. Effects of the laser spot position, distribution of the force exerted on the cantilever, and difference in the detection scheme on the obtained transfer function are discussed in comparison with theoretical predictions by other research groups. A preliminary result of viscoelasticity spectrum measurement of a single dextran chain is shown and is compared with a recent theoretical calculation. PMID:19256651</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApPhA.104..583S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApPhA.104..583S"><span id="translatedtitle">Structural and <span class="hlt">magnetic</span> properties of Mn-doped anatase TiO2 films synthesized by <span class="hlt">atomic</span> layer deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sellers, Meredith C. K.; Seebauer, Edmund G.</p> <p>2011-08-01</p> <p>Mn-doped anatase TiO2 (Mn: 1.2, 2.4 at%) thin films were grown on Si(100) via <span class="hlt">atomic</span> layer deposition (ALD). The synthesis utilized Ti(OCH(CH3)2)4 and H2O as ALD precursors and Mn(DPM)3 as a dopant source. X-ray photoelectron spectroscopy measurements indicate that Mn is successfully doped in the TiO2 matrix and reveal information about film composition and elemental chemical states. Microstructure, crystallinity, and density were investigated with scanning electron microscopy, X-ray diffraction, and X-ray reflectivity. All ALD-synthesized films exhibited room-temperature ferromagnetism; the microstructure, density, and <span class="hlt">magnetic</span> field-dependent <span class="hlt">magnetization</span> of the TiO2 varied with the concentration of Mn. ALD permits precise composition and thickness control, and much higher process throughput compared to alternative techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22350804','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22350804"><span id="translatedtitle">Temperature and bias-voltage dependence of <span class="hlt">atomic</span>-layer-deposited HfO{sub 2}-based <span class="hlt">magnetic</span> tunnel junctions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fabretti, Savio; Zierold, Robert; Nielsch, Kornelius; Voigt, Carmen; Ronning, Carsten; Peretzki, Patrick; Seibt, Michael; Thomas, Andy</p> <p>2014-09-29</p> <p><span class="hlt">Magnetic</span> tunnel junctions with HfO{sub 2} tunnel barriers were prepared through a combination of magnetron sputtering and <span class="hlt">atomic</span> layer deposition. We investigated the tunneling transport behavior, including the tunnel magnetoresistance ratio and the current-voltage characteristics between room temperature and 2 K. Here, we achieved a tunneling magneto resistance ratio of 10.3% at room temperature and 19.3% at 2 K. Furthermore, we studied the bias-voltage and temperature dependencies and compared the results with those of commonly used alumina- and magnesia-based <span class="hlt">magnetic</span> tunnel junctions. We observed a polycrystalline/amorphous electrode-barrier system via high-resolution transmission electron microscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......301S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......301S"><span id="translatedtitle">Interaction of <span class="hlt">magnetism</span> with <span class="hlt">atomic</span> lattice geometry and nanoscale geometric frustration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Subramanian, Hemachander</p> <p></p> <p>From lodestones to quantum computers, <span class="hlt">magnetism</span> has been intricately entwined with scientific and technological development of humankind for millenia. A short chronological list of important experiments, theories and effects connected with <span class="hlt">magnetism</span> that substantially altered the course of human understanding of the physical world: Magnetites, navigation, the concept of fields, electromagnetism and Maxwell's equations, Zeeman effect, Curie's law, special relativity, quantum mechanical spin, cooperative phenomena, phase transitions, frustration, Ising model, quantum statistical mechanics, <span class="hlt">magnetic</span> memories, high-temperature superconductivity, spintronics and so on. The seemingly uninteresting effect of <span class="hlt">magnetic</span> anisotropy is probably the only observable effect that requires for its explanation, both quantum mechanics and special relativity, the two towering theories of twentieth century. This effect arises from the interaction between the spin part and the spatial part of an electron's wavefunction, which is due to the relativistic motion of electron around the nucleus. Without such an interaction, <span class="hlt">magnetism</span> would have remained as a pure academic interest. The macroscopic manifestation of this spin-orbit interaction, <span class="hlt">magnetic</span> anisotropy, is the central theme of this thesis. In the first chapter, we explore how ionic displacements in a solid and <span class="hlt">magnetization</span> directions are tied together through spin-orbit coupling. <span class="hlt">Magnetic</span> ion doped semiconductor Gallium Manganese Arsenide shows rich and intricate <span class="hlt">magnetic</span> anisotropies, with one of the anisotropy components unexpected from symmetry grounds. This chapter explains how the inclusion of displacements of the impurity ion helps us explain the apparently unexpected observation of uniaxial <span class="hlt">magnetic</span> anisotropy in the above material. In the second chapter, we utilize this <span class="hlt">magnetic</span> anisotropy by bringing together two materials, one with very high and another with negligible anisotropy, to introduce <span class="hlt">magnetic</span> frustration in a nanoscale system. The effect of frustration, where not all the forces or constraints can be simultaneously satisfied, results in rich energetic behavior where the system accesses different sets of energy minima for different strengths of external rotating <span class="hlt">magnetic</span> field. We propose and computationally demonstrate the functioning of a ternary logic device using the above nanoscale system. Five appendices are included, elaborating on technical details, detailed derivations, explanation of constants and summary of papers whose results were used in the thesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21316903','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21316903"><span id="translatedtitle">Nuclear Spin Maser at Highly Stabilized Low <span class="hlt">Magnetic</span> Field and Search for <span class="hlt">Atomic</span> EDM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yoshimi, A.; Asahi, K.; Inoue, T.; Uchida, M.; Hatakeyama, N.; Tsuchiya, M.; Kagami, S.</p> <p>2009-08-04</p> <p>A nuclear spin maser is operated at a low static field through an active feedback scheme based on an optical nuclear spin detection and succeeding spin control by a transverse field application. The frequency stability of this optical-coupling spin maser is improved by installation of a low-noise current source for a solenoid <span class="hlt">magnet</span> producing a static <span class="hlt">magnetic</span> field in the maser operation. Experimental devices for application of the maser to EDM experiment are being developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26905782','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26905782"><span id="translatedtitle"><span class="hlt">Atomic</span>-Scale Structure and Local Chemistry of CoFeB-MgO <span class="hlt">Magnetic</span> Tunnel Junctions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Zhongchang; Saito, Mitsuhiro; McKenna, Keith P; Fukami, Shunsuke; Sato, Hideo; Ikeda, Shoji; Ohno, Hideo; Ikuhara, Yuichi</p> <p>2016-03-01</p> <p><span class="hlt">Magnetic</span> tunnel junctions (MTJs) constitute a promising building block for future nonvolatile memories and logic circuits. Despite their pivotal role, spatially resolving and chemically identifying each individual stacking layer remains challenging due to spatially localized features that complicate characterizations limiting understanding of the physics of MTJs. Here, we combine advanced electron microscopy, spectroscopy, and first-principles calculations to obtain a direct structural and chemical imaging of the <span class="hlt">atomically</span> confined layers in a CoFeB-MgO MTJ, and clarify <span class="hlt">atom</span> diffusion and interface structures in the MTJ following annealing. The combined techniques demonstrate that B diffuses out of CoFeB electrodes into Ta interstitial sites rather than MgO after annealing, and CoFe bonds <span class="hlt">atomically</span> to MgO grains with an epitaxial orientation relationship by forming Fe(Co)-O bonds, yet without incorporation of CoFe in MgO. These findings afford a comprehensive perspective on structure and chemistry of MTJs, helping to develop high-performance spintronic devices by atomistic design. PMID:26905782</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IJTFM.131..499I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IJTFM.131..499I"><span id="translatedtitle">Effect of Anisotropic Incidence and <span class="hlt">Atomic</span> Arrangement of CoFe System <span class="hlt">Magnetic</span> Thin Films for the GHz Frequency in the Carousel Sputtering Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Imaizumi, Ryoichi; Munakata, Makoto; Ohkoshi, Masatoshi; Maki, Kouichirou</p> <p></p> <p>To increase the uniaxial- <span class="hlt">magnetic</span> anisotropy in thin-film materials is the key issue for the micro-<span class="hlt">magnetic</span> devices driven in a GHz frequency. It is known that an especially large uniaxial- <span class="hlt">magnetic</span> anisotropy was induced only by the carousel sputtering method. In this paper, an <span class="hlt">atomic</span> deposition process of the CoFeB and CoFe films were analyzed by using simulation of Kinetic Theory of Gases. The result exhibited that the sputtered particles had remarkably anisotropic incidence to the substrate leading to different <span class="hlt">atomic</span> distances with respect to the incident direction, which results in a <span class="hlt">magnetic</span> elastic effect. These sputtered particles with the anisotropic incidence give rise to a main cause of the higher uniaxial- <span class="hlt">magnetic</span> anisotropy of the films.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21611729','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21611729"><span id="translatedtitle">Fe/Si(001) Ferromagnetic Layers: Reactivity, Local <span class="hlt">Atomic</span> Structure and <span class="hlt">Magnetism</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lungu, G. A.; Costescu, R. M.; Husanu, M. A.; Gheorghe, N. G.</p> <p>2011-10-03</p> <p>Ultrathin ferromagnetic Fe layers on Si(001) have recently been synthesized using the molecular beam epitaxy (MBE) technique, and their structural and <span class="hlt">magnetic</span> properties, as well as their interface reactivity have been investigated. The study was undertaken as function of the amount of Fe deposited and of substrate temperature. The interface reactivity was characterized by Auger electron spectroscopy (AES). The surface structure was characterized by low-energy electron diffraction (LEED). The <span class="hlt">magnetism</span> was investigated by magneto-optical Kerr effect (MOKE). A higher deposition temperature stabilizes a better surface ordering, but it also enhances Fe and Si interdiffusion and it therefore decreases the <span class="hlt">magnetism</span>. Despite the rapid disappearance of the long range order with Fe deposition at room temperature, the material exhibits a significant uniaxial in-plane <span class="hlt">magnetic</span> anisotropy. For the Fe deposition performed at high temperature (500 deg. C), a weak ferromagnetism is still observed, with saturation <span class="hlt">magnetization</span> of about 10% of the value obtained previously. MOKE studies allowed inferring the main properties of the distinct formed layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCo...710395L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCo...710395L"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B. Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles--the Majorana bound states--can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26791080','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26791080"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles--the Majorana bound states--can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field. PMID:26791080</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4735899','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4735899"><span id="translatedtitle">Manipulating Majorana zero modes on <span class="hlt">atomic</span> rings with an external <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Jian; Neupert, Titus; Bernevig, B. Andrei; Yazdani, Ali</p> <p>2016-01-01</p> <p>Non-Abelian quasiparticles have been predicted to exist in a variety of condensed matter systems. Their defining property is that an adiabatic braid between two of them results in a non-trivial change of the quantum state of the system. The simplest non-Abelian quasiparticles—the Majorana bound states—can occur in one-dimensional electronic nano-structures proximity-coupled to a bulk superconductor. Here we propose a set-up, based on chains of <span class="hlt">magnetic</span> adatoms on the surface of a thin-film superconductor, in which the control over an externally applied <span class="hlt">magnetic</span> field suffices to create and manipulate Majorana bound states. We consider specifically rings of adatoms and show that they allow for the creation, annihilation, adiabatic motion and braiding of pairs of Majorana bound states by varying the magnitude and orientation of the external <span class="hlt">magnetic</span> field. PMID:26791080</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPA....6b5005H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPA....6b5005H"><span id="translatedtitle"><span class="hlt">Atomic</span> scale understanding of <span class="hlt">magnetic</span> properties in Ni50Fe35Co15</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herojit Singh, L.; Govindaraj, R.; Ravishankar, C.; Rajagopalan, S.; Amarendra, G.</p> <p>2016-02-01</p> <p>Mössbauer spectroscopic studies have been carried out at different temperatures across ferromagnetic to paramagnetic transition in Ni50Fe35Co15 and the evolution of hyperfine parameters such as centre shift and <span class="hlt">magnetic</span> hyperfine fields with temperature has been studied. Mössbauer spectrum obtained at 300 K in Ni50Fe35Co15 exhibiting fcc crystal structure is a six line pattern with the mean value of the hyperfine field close to 33 Tesla. Ferromagnetic to paramagnetic transition has been observed to occur in this system around 895 K matching with that of <span class="hlt">magnetization</span> results. Debye temperature of this nickel rich alloy is deduced to be around 470 K matching with that of Ni. Effect of prolonged annealing at 750 K on the <span class="hlt">magnetic</span> property is also investigated with respect to the thermal stability of the alloy .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/963595','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/963595"><span id="translatedtitle">Electronic and <span class="hlt">magnetic</span> properties of graphene absorbed with S <span class="hlt">atom</span>: A first-principles study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou, Yungang; Zu, Xiaotao T.; Gao, Fei; Xiao, H. Y.; Lv, H. F.</p> <p>2009-05-15</p> <p>Stable configuration, electronic structures, and <span class="hlt">magnetic</span> behaviors for S adsorption on graphene have been investigated by first-principles calculations. It is found that the adsorption site of S on graphene is coverage dependent. As the increase of coverage from 0 to 0.5 ML, the preferred site is changed from bridge to hollow site. For the adsorption of S at bridge site, no <span class="hlt">magnetic</span> moment is detected, and the adsorption is characterized by strong hybridization between the S 2s state and graphene σ states. For the adsorption of S at hollow site, a <span class="hlt">magnetic</span> moment of 1.98 μB was induced. In this case, the hybridization occurs between S 2p states and graphene π states. Furthermore, from the investigation of the surface potential energy curve, we find that graphene is a suitable candidate for the S storage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3687..335K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3687..335K"><span id="translatedtitle">Application of <span class="hlt">atomic</span> force microscopy for investigation of <span class="hlt">magnetic</span> structure of steels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalashnikov, I. S.; Klimchitskaya, G. L.; Prioli, R.; Zanette, S. I.; Caride, A. O.; Acselrad, O.; Silva, E. M.; Simao, R. A.</p> <p>1999-05-01</p> <p><span class="hlt">Magnetic</span> force microscopy (MFM) is used for investigation of <span class="hlt">magnetic</span> structure in steels Fe - 28 Mn - 8.5 Al - 1C - 1.4Si under the different regimes of isotermic aging. A theoretical model for the MFM image of such a structure is developed. Also the calculation method of the van der Waals forces is considered which may be used for the interpretation of the topography measurements. The utility of MFM data is demonstrated for testing of micromagnetic structure of steels and conditions are formulated which should be fulfilled to look into its details.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MAR.G7010H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MAR.G7010H"><span id="translatedtitle">Local <span class="hlt">Atomic</span> Structure and <span class="hlt">Magnetism</span> in Amorphous FexSi1-x Thin Films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hellman, Frances; Zhang, Yanning; Bordel, Catherine; Stone, Kevin; Jenkins, Catherine; Smith, David; Hu, J.; Wu, Ruqian; Heald, Steve; Kortright, Jeff; Karel, Julie</p> <p>2014-03-01</p> <p>Amorphous FexSi1-x thin films exhibit a large enhancement in M compared to crystalline films with the same composition (0.45< x<0.75). XMCD shows enhancement in both spin and orbital moments. Density functional theory (DFT) calculations reproduce this enhanced <span class="hlt">magnetization</span>. DFT and EXAFS show the amorphous materials have decreased number of nearest neighbors and reduced number density relative to crystalline samples of same x, which leads to the enhanced moment. Thanks to DOE BES LBNL <span class="hlt">magnetism</span> program for support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.691a2020S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.691a2020S"><span id="translatedtitle">Radiation Trapping in a Cold and Dense <span class="hlt">Atomic</span> Ensemble in a <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokolov, Igor</p> <p>2016-02-01</p> <p>We report a theoretical investigation of cooperative spontaneous decay of <span class="hlt">atomic</span> excitation in cold ensemble under condition that average interatomic separation is comparable with resonant light wavelength. We show that magnetostatic field causes some acceleration of decay at shot time interval upon turn off the excitation pulse and essential decreasing of decay rate of long-lived sub-radiant states. The dependence of this effect on duration of excitation pulse as well as on its carrier frequency is considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1163590','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1163590"><span id="translatedtitle">Defect propagation in one-, two-, and three-dimensional compounds doped by <span class="hlt">magnetic</span> <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Furrer, A.; Podlesnyak, A.; Krämer, K. W.; Strässle, Th.</p> <p>2014-10-29</p> <p>Inelastic neutron scattering experiments were performed to study manganese(II) dimer excitations in the diluted one-, two-, and three-dimensional compounds CsMn<sub>x</sub>Mg<sub>1-x</sub>Br<sub>3</sub>, K<sub>2</sub>Mn<sub>x</sub>Zn<sub>1-x</sub>F<sub>4</sub>, and KMn<sub>x</sub>Zn<sub>1-x</sub>F<sub>3</sub> (x≤0.10), respectively. The transitions from the ground-state singlet to the excited triplet, split into a doublet and a singlet due to the single-ion anisotropy, exhibit remarkable fine structures. These unusual features are attributed to local structural inhomogeneities induced by the dopant Mn <span class="hlt">atoms</span> which act like lattice defects. Statistical models support the theoretically predicted decay of <span class="hlt">atomic</span> displacements according to 1/r<sup>2</sup>, 1/r, and constant (for three-, two-, and one-dimensional compounds, respectively) where r denotes the distance of the displaced <span class="hlt">atoms</span> from the defect. In conclusion, the observed fine structures allow a direct determination of the local exchange interactions J, and the local intradimer distances R can be derived through the linear law dJ/dR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1163590-defect-propagation-one-two-three-dimensional-compounds-doped-magnetic-atoms','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1163590-defect-propagation-one-two-three-dimensional-compounds-doped-magnetic-atoms"><span id="translatedtitle">Defect propagation in one-, two-, and three-dimensional compounds doped by <span class="hlt">magnetic</span> <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Furrer, A.; Podlesnyak, A.; Krämer, K. W.; Strässle, Th.</p> <p>2014-10-29</p> <p>Inelastic neutron scattering experiments were performed to study manganese(II) dimer excitations in the diluted one-, two-, and three-dimensional compounds CsMnxMg1-xBr3, K2MnxZn1-xF4, and KMnxZn1-xF3 (x≤0.10), respectively. The transitions from the ground-state singlet to the excited triplet, split into a doublet and a singlet due to the single-ion anisotropy, exhibit remarkable fine structures. These unusual features are attributed to local structural inhomogeneities induced by the dopant Mn <span class="hlt">atoms</span> which act like lattice defects. Statistical models support the theoretically predicted decay of <span class="hlt">atomic</span> displacements according to 1/r2, 1/r, and constant (for three-, two-, and one-dimensional compounds, respectively) where r denotes the distance ofmore » the displaced <span class="hlt">atoms</span> from the defect. In conclusion, the observed fine structures allow a direct determination of the local exchange interactions J, and the local intradimer distances R can be derived through the linear law dJ/dR.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26348798','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26348798"><span id="translatedtitle"><span class="hlt">Atomic</span>-Scale <span class="hlt">Magnetism</span> of Cr-Doped Bi2Se3 Thin Film Topological Insulators.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Wenqing; West, Damien; He, Liang; Xu, Yongbing; Liu, Jun; Wang, Kejie; Wang, Yong; van der Laan, Gerrit; Zhang, Rong; Zhang, Shengbai; Wang, Kang L</p> <p>2015-10-27</p> <p><span class="hlt">Magnetic</span> doping is the most common method for breaking time-reversal-symmetry surface states of topological insulators (TIs) to realize novel physical phenomena and to create beneficial technological applications. Here we present a study of the <span class="hlt">magnetic</span> coupling of a prototype <span class="hlt">magnetic</span> TI, that is, Cr-doped Bi2Se3, in its ultrathin limit which is expected to give rise to quantum anomalous Hall (QAH) effect. The high quality Bi2-xCrxSe3 epitaxial thin film was prepared using molecular beam epitaxy (MBE), characterized with scanning transimission electron microscopy (STEM), electrical magnetotransport, and X-ray <span class="hlt">magnetic</span> circularly dichroism (XMCD) techniques, and the results were simulated using density functional theory (DFT) with spin-orbit coupling (SOC). We observed a sizable spin moment mspin = (2.05 ± 0.20) μB/Cr and a small and negative orbital moment morb = (-0.05 ± 0.02) μB/Cr of the Bi1.94Cr0.06Se3 thin film at 2.5 K. A remarkable fraction of the (CrBi-CrI)(3+) antiferromagnetic dimer in the Bi2-xCrxSe3 for 0.02 < x < 0.40 was obtained using first-principles simulations, which was neglected in previous studies. The spontaneous coexistence of ferro- and antiferromagnetic Cr defects in Bi2-xCrxSe3 explains our experimental observations and those based on conventional magnetometry which universally report <span class="hlt">magnetic</span> moments significantly lower than 3 μB/Cr predicted by Hund's rule. PMID:26348798</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26923173','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26923173"><span id="translatedtitle"><span class="hlt">Magnetic</span> Properties of a Single-Molecule Lanthanide-Transition-Metal Compound Containing 52 Gadolinium and 56 Nickel <span class="hlt">Atoms</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Da-Peng; Lin, Xin-Ping; Zhang, Hui; Zheng, Xiu-Ying; Zhuang, Gui-Lin; Kong, Xiang-Jian; Long, La-Sheng; Zheng, Lan-Sun</p> <p>2016-03-24</p> <p>Monodisperse metal clusters provide a unique platform for investigating <span class="hlt">magnetic</span> exchange within molecular <span class="hlt">magnets</span>. Herein, the core-shell structure of the monodisperse molecule <span class="hlt">magnet</span> of [Gd52 Ni56 (IDA)48 (OH)154 (H2 O)38 ]@SiO2 (1 a@SiO2 ) was prepared by encapsulating one high-nuclearity lanthanide-transition-metal compound of [Gd52 Ni56 (IDA)48 (OH)154 (H2 O)38 ]⋅(NO3 )18 ⋅164 H2 O (1) (IDA=iminodiacetate) into one silica nanosphere through a facile one-pot microemulsion method. 1 a@SiO2 was characterized using transmission electron microscopy, N2 adsorption-desorption isotherms, and inductively coupled plasma-<span class="hlt">atomic</span> emission spectrometry. <span class="hlt">Magnetic</span> investigation of 1 and 1 a revealed J1 =0.25 cm(-1) , J2 =-0.060 cm(-1) , J3 =-0.22 cm(-1) , J4 =-8.63 cm(-1) , g=1.95, and z J=-2.0×10(-3)  cm(-1) for 1, and J1 =0.26 cm(-1) , J2 =-0.065 cm(-1) , J3 =-0.23 cm(-1) , J4 =-8.40 cm(-1)  g=1.99, and z J=0.000 cm(-1) for 1 a@SiO2 . The z J=0 in 1 a@SiO2 suggests that weak antiferromagnetic coupling between the compounds is shielded by silica nanospheres. PMID:26923173</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987PhyS...35..146B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987PhyS...35..146B"><span id="translatedtitle">The Observation of Transitions Between Rydberg States of <span class="hlt">Atomic</span> Chlorine by Laser <span class="hlt">Magnetic</span> Resonance at 6.7 μm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, J. M.; Comben, E. R.; Bohle, W.; Zeitz, D.; Urban, W.</p> <p>1987-02-01</p> <p>Transitions between Rydberg states of <span class="hlt">atomic</span> chlorine have been detected between 1477 and 1507 cm-1 by the technique of carbon monoxide laser <span class="hlt">magnetic</span> resonance (LMR). Transitions have been observed in both emission and absorption. The spectra have been assigned for those transitions involving levels which have been identified previously. However, several more resonances are unassigned, revealing the presence of previously unidentified states of <span class="hlt">atomic</span> chlorine. Many of the lines show resolved nuclear hyperfine structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21406811','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21406811"><span id="translatedtitle"><span class="hlt">Atomic</span> and <span class="hlt">magnetic</span> order in the shape memory alloy Mn2NiGa.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brown, P J; Kanomata, T; Neumann, K; Neumann, K U; Ouladdiaf, B; Sheikh, A; Ziebeck, K R A</p> <p>2010-12-22</p> <p><span class="hlt">Magnetization</span> and high resolution neutron powder diffraction measurements on the <span class="hlt">magnetic</span> shape memory alloy Mn(2)NiGa have confirmed that it is ferromagnetic with a Curie temperature above 500 K. The compound undergoes a broad structural phase transformation ΔT ∼ 90 K with a mean transition temperature T(M) ∼ 270 K. The high temperature parent phase is cubic (a = 5.937 Å) and has a modified L 2(1) structure. At 500 K the ordered <span class="hlt">magnetic</span> moment essentially all on the 4a site is 1.35 μ(B)/Mn. The low temperature martensite has space group I4/mmm and is related to the cubic phase through a Bain transformation a(tet) = (a(cub) + b(cub))/2, b(tet) = (a(cub) - b(cub)) and c(tet) = c(cub) in which the change in cell volume is < 2.6%. In this structure at 5 K the ordered moment of ≈2.3 μ(B) is again found to be confined to the sites with full Mn occupation and is aligned parallel to c. Neutron diffraction patterns obtained at 5 K suggested the presence of a weak incommensurate antiferromagnetic phase characterized by either a ((1/3)0(1/3)) or (00(1/3)) propagation vector. PMID:21406811</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/509045','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/509045"><span id="translatedtitle"><span class="hlt">Magnetism</span> of Rh and Ru <span class="hlt">atoms</span>, clusters, and monolayers on Au and Ag surfaces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Beckmann, H.; Bergmann, G.</p> <p>1997-06-01</p> <p>The <span class="hlt">magnetic</span> character of Rh and Ru on the surface of Au and Ag is investigated by means of weak localization (WL) and the anomalous Hall effect (AHE). Dephasing of the conduction electrons in WL is the most sensitive method to detect <span class="hlt">magnetic</span> surface impurities. The Au/Rh and Au/Ru systems are investigated in the range between 1/100 of a monolayer of Rh (Ru) and several monolayers of Rh (Ru). We observe a small dephasing by Rh clusters and no dephasing by single Rh surface impurities, while single Ru surface impurities cause already a finite but small dephasing. We suggest that the dephasing is caused by small fluctuating <span class="hlt">magnetic</span> moments of the order of 0.1(0.4){mu}{sub B}. For a coverage of one monolayer of Rh we observe a maximum in the dephasing. However, we do not observe a ferromagnetic Rh monolayer as predicted in a number of theoretical papers. Similarly, a Ru monolayer on the surface of Au or Ag does not show ferromagnetism. The absence of an AHE in the Rh and Ru monolayers excludes ferromagnetism as well. For Rh the dephasing increases again when the Rh coverage exceeds two monolayers, suggesting that pure bulk Rh shows spin fluctuations. {copyright} {ital 1997} {ital The American Physical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JETPL.101..258V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JETPL.101..258V"><span id="translatedtitle">In situ study of <span class="hlt">atomic</span>-vacancy ordering in stoichiometric titanium monoxide by the <span class="hlt">magnetic</span> susceptibility</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valeeva, A. A.; Nazarova, S. Z.; Rempel, A. A.</p> <p>2015-02-01</p> <p>An in situ temperature study of a variation in the degree of long-range order in stoichiometric titanium monoxide has been performed by the <span class="hlt">magnetic</span> susceptibility method. The measurements have been performed on annealed and quenched titanium monoxide in the temperature range from 300 to 1200 K. It has been found that the degree of long-range order depends on the regime and temperature of annealing of the initial samples. The degree of long-range order in the process of measurement of the <span class="hlt">magnetic</span> susceptibility varies from 0.21 to 1.00; the larger the degree of long-range order, the smaller the <span class="hlt">magnetic</span> susceptibility. Furthermore, the long-range order parameter decreases with an increase in the temperature above 1200 K and vanishes sharply at the order-disorder transition temperature. According to the results of this work, the critical long-range order parameter is 0.21 and the temperature of the nonequilibrium disorder-order transition is about 1073 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EL.....8837003G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EL.....8837003G"><span id="translatedtitle">Accurate evaluation of <span class="hlt">magnetic</span> coupling between <span class="hlt">atoms</span> with numerous open shells: An ab initio method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gellé, A.; Varignon, J.; Lepetit, M.-B.</p> <p>2009-11-01</p> <p>We propose a new ab initio method designed for the accurate calculation of effective exchange integrals between <span class="hlt">atoms</span> with numerous open shells. This method applies to ferromagnetic as well as antiferromagnetic exchange, direct or ligand-mediated exchange. Test calculations on high spin transition metal oxides such as KNiF3, Ba2CoS3 or YMnO3 exhibit a very good accuracy compared either to the best ab initio calculations —when those are feasible— and with experimental evaluations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22409981','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22409981"><span id="translatedtitle">Interaction transfer of silicon <span class="hlt">atoms</span> forming Co silicide for Co/√(3)×√(3)R30°-Ag/Si(111) and related <span class="hlt">magnetic</span> properties</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang, Cheng-Hsun-Tony; Fu, Tsu-Yi; Tsay, Jyh-Shen</p> <p>2015-05-07</p> <p>Combined scanning tunneling microscopy, Auger electron spectroscopy, and surface magneto-optic Kerr effect studies were employed to study the microscopic structures and <span class="hlt">magnetic</span> properties for ultrathin Co/√(3)×√(3)R30°-Ag/Si(111). As the annealing temperature increases, the upward diffusion of Si <span class="hlt">atoms</span> and formation of Co silicides occurs at temperature above 400 K. Below 600 K, the √(3)×√(3)R30°-Ag/Si(111) surface structure persists. We propose an interaction transferring mechanism of Si <span class="hlt">atoms</span> across the √(3)×√(3)R30°-Ag layer. The upward transferred Si <span class="hlt">atoms</span> react with Co <span class="hlt">atoms</span> to form Co silicide. The step height across the edge of the island, a separation of 0.75 nm from the analysis of the 2 × 2 structure, and the calculations of the normalized Auger signal serve as strong evidences for the formation of CoSi{sub 2} at the interface. The interaction transferring mechanism for Si <span class="hlt">atoms</span> enhances the possibility of interactions between Co and Si <span class="hlt">atoms</span>. The smoothness of the surface is advantage for that the easy axis of <span class="hlt">magnetization</span> for Co/√(3)×√(3)R30°-Ag/Si(111) is in the surface plane. This provides a possible way of growing flat <span class="hlt">magnetic</span> layers on silicon substrate with controllable silicide formation and shows potential applications in spintronics devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcSpe.107..115Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcSpe.107..115Z"><span id="translatedtitle">Novel ion imprinted <span class="hlt">magnetic</span> mesoporous silica for selective <span class="hlt">magnetic</span> solid phase extraction of trace Cd followed by graphite furnace <span class="hlt">atomic</span> absorption spectrometry detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Bingshan; He, Man; Chen, Beibei; Hu, Bin</p> <p>2015-05-01</p> <p>Determination of trace Cd in environmental, biological and food samples is of great significance to toxicological research and environmental pollution monitoring. While the direct determination of Cd in real-world samples is difficult due to its low concentration and the complex matrix. Herein, a novel Cd(II)-ion imprinted <span class="hlt">magnetic</span> mesoporous silica (Cd(II)-II-MMS) was prepared and was employed as a selective <span class="hlt">magnetic</span> solid-phase extraction (MSPE) material for extraction of trace Cd in real-world samples followed by graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS) detection. Under the optimized conditions, the detection limit of the proposed method was 6.1 ng L- 1 for Cd with the relative standard deviation (RSD) of 4.0% (c = 50 ng L- 1, n = 7), and the enrichment factor was 50-fold. To validate the proposed method, Certified Reference Materials of GSBZ 50009-88 environmental water, ZK018-1 lyophilized human urine and NIES10-b rice flour were analyzed and the determined values were in a good agreement with the certified values. The proposed method exhibited a robust anti-interference ability due to the good selectivity of Cd(II)-II-MMS toward Cd(II). It was successfully employed for the determination of trace Cd(II) in environmental water, human urine and rice samples with recoveries of 89.3-116%, demonstrating that the proposed method has good application potential in real world samples with complex matrix.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490583','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490583"><span id="translatedtitle">Fe{sub 2-x}Co{sub x}MnSi (x = 0, 1 and 2) Heusler alloys: Structural, <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> site disorder properties</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bhatt, Harsh; Mukadam, M. D.; Meena, S. S.; Yusuf, S. M.</p> <p>2015-06-24</p> <p>The Heusler alloy series Fe{sub 2-x}Co{sub x}MnSi (x = 0, 1 and 2) is theoretically predicted to be half metallic. We prepared the sample series and determined the structural and <span class="hlt">magnetic</span> properties to check if these materials are suitable for spintronics applications. The Curie temperatures of two of the alloys have been found to be well above the room temperature. But the presence of elements with <span class="hlt">atoms</span> of similar size leads to <span class="hlt">atomic</span> site disorder in these alloys, which may destroy the half metallic nature. The <span class="hlt">atomic</span> site disorder has been confirmed by Mössbauer spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27228502','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27228502"><span id="translatedtitle">Electrical and mechanical controlling of the kinetic and <span class="hlt">magnetic</span> properties of hydrogen <span class="hlt">atoms</span> on free-standing silicene.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Podsiadły-Paszkowska, Agata; Krawiec, Mariusz</p> <p>2016-07-20</p> <p>Effects of strain, charge doping and external electric field on kinetic and <span class="hlt">magnetic</span> properties of hydrogen <span class="hlt">atoms</span> on a free-standing silicene layer are investigated by first-principles density functional theory. It was found that the charge doping and strain are the most effective ways of changing the hydrogen-silicene binding energy, but they can only raise its value. The perpendicular external electric field can also lower it albeit in a narrower range. The strain has also the strongest impact on diffusion processes, and the diffusion barrier can be modified up to 50% of its unstrained value. The adsorption of hydrogen <span class="hlt">atoms</span> results in a locally antiferromagnetic ground state with the effective exchange constant of approximately 1 eV. The system can easily be driven into a nonmagnetic phase by the charge doping and strain. The obtained results are very promising in view of the silicene functionalization and potential applications of silicene in fields of modern nanoelectronics and spintronics. PMID:27228502</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24988469','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24988469"><span id="translatedtitle">Sub-nanometer <span class="hlt">atomic</span> layer deposition for spintronics in <span class="hlt">magnetic</span> tunnel junctions based on graphene spin-filtering membranes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martin, Marie-Blandine; Dlubak, Bruno; Weatherup, Robert S; Yang, Heejun; Deranlot, Cyrile; Bouzehouane, Karim; Petroff, Frédéric; Anane, Abdelmadjid; Hofmann, Stephan; Robertson, John; Fert, Albert; Seneor, Pierre</p> <p>2014-08-26</p> <p>We report on the successful integration of low-cost, conformal, and versatile <span class="hlt">atomic</span> layer deposited (ALD) dielectric in Ni–Al2O3–Co <span class="hlt">magnetic</span> tunnel junctions (MTJs) where the Ni is coated with a spin-filtering graphene membrane. The ALD tunnel barriers, as thin as 0.6 nm, are grown layer-by-layer in a simple, low-vacuum, ozone-based process, which yields high-quality electron-transport barriers as revealed by tunneling characterization. Even under these relaxed conditions, including air exposure of the interfaces, a significant tunnel magnetoresistance is measured highlighting the robustness of the process. The spin-filtering effect of graphene is enhanced, leading to an almost fully inversed spin polarization for the Ni electrode of −42%. This unlocks the potential of ALD for spintronics with conformal, layer-by-layer control of tunnel barriers in <span class="hlt">magnetic</span> tunnel junctions toward low-cost fabrication and down-scaling of tunnel resistances. PMID:24988469</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NatSR...4E5303K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NatSR...4E5303K"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and temperature sensing with <span class="hlt">atomic</span>-scale spin defects in silicon carbide</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kraus, H.; Soltamov, V. A.; Fuchs, F.; Simin, D.; Sperlich, A.; Baranov, P. G.; Astakhov, G. V.; Dyakonov, V.</p> <p>2014-07-01</p> <p>Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. <span class="hlt">Atomic</span>-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of -1.1 MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4081891','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4081891"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and temperature sensing with <span class="hlt">atomic</span>-scale spin defects in silicon carbide</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kraus, H.; Soltamov, V. A.; Fuchs, F.; Simin, D.; Sperlich, A.; Baranov, P. G.; Astakhov, G. V.; Dyakonov, V.</p> <p>2014-01-01</p> <p>Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. <span class="hlt">Atomic</span>-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of −1.1 MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response. PMID:24993103</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CPL...646..148C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CPL...646..148C"><span id="translatedtitle">The <span class="hlt">magnetic</span> and transport properties of edge passivated silicene nanoribbon by Mn <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Changpeng; Zhu, Ziqing; Zha, Dace; Qi, Meilan; Wu, Jinping</p> <p>2016-02-01</p> <p>The effect of chemical doping on the ZSiNRs with Mn as passivating element replacing H <span class="hlt">atoms</span> at one edge are investigated by first-principles calculations. The structures optimized in the typical ferromagnetic and antiferromagnetic coupling show that the system leads to an AFM state and achieve half-metallic properties. Also, our first principle approach based on the Keldysh non-equilibrium Green's function method gives the spin-dependent transport properties of the device. When the system changes from parallel to antiparallel configuration. The spin-up current increases rapidly while the spin-up current is still depressed. Further, it is found that the system is a quite good spin filtering device with nearly 80% spin filtering efficiency at a wide bias voltage region and therefore suitable for applications. The mechanisms for these phenomena are proposed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24993103','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24993103"><span id="translatedtitle"><span class="hlt">Magnetic</span> field and temperature sensing with <span class="hlt">atomic</span>-scale spin defects in silicon carbide.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kraus, H; Soltamov, V A; Fuchs, F; Simin, D; Sperlich, A; Baranov, P G; Astakhov, G V; Dyakonov, V</p> <p>2014-01-01</p> <p>Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. <span class="hlt">Atomic</span>-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of -1.1?MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response. PMID:24993103</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvB..81n4431X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvB..81n4431X"><span id="translatedtitle">Liquids in multiorbital SU(N) <span class="hlt">magnets</span> made up of ultracold alkaline-earth <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Cenke</p> <p>2010-04-01</p> <p>In this work we study one family of liquid states of k -orbital SU(N) spin systems, focusing on the case of k=2 which can be realized by ultracold alkaline-earth <span class="hlt">atoms</span> trapped in optical lattices, with N as large as 10. Five different algebraic liquid states with selectively coupled charge, spin, and orbital quantum fluctuations are considered. The algebraic liquid states can be stabilized with large enough N and the scaling dimension of physical order parameters is calculated using a systematic 1/N expansion. The phase transitions between these liquid states are also studied and all the algebraic liquid states discussed in this work can be obtained from one “mother” state with SU(2)×U(1) gauge symmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...814..112F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...814..112F"><span id="translatedtitle">Charting the Interstellar <span class="hlt">Magnetic</span> Field causing the Interstellar Boundary Explorer (IBEX) Ribbon of Energetic Neutral <span class="hlt">Atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frisch, P. C.; Berdyugin, A.; Piirola, V.; Magalhaes, A. M.; Seriacopi, D. B.; Wiktorowicz, S. J.; Andersson, B.-G.; Funsten, H. O.; McComas, D. J.; Schwadron, N. A.; Slavin, J. D.; Hanson, A. J.; Fu, C.-W.</p> <p>2015-12-01</p> <p>The interstellar <span class="hlt">magnetic</span> field (ISMF) near the heliosphere is a fundamental component of the solar galactic environment that can only be studied using polarized starlight. The results of an ongoing survey of the linear polarizations of local stars are analyzed with the goal of linking the ISMF that shapes the heliosphere to the nearby field in interstellar space. We present new results on the direction of the <span class="hlt">magnetic</span> field within 40 pc obtained from analyzing polarization data using a merit function that determines the field direction that provides the best fit to the polarization data. Multiple <span class="hlt">magnetic</span> components are identified, including a dominant interstellar field, {B}{POL}, that is aligned with the direction ℓ, b = 36.°2, 49.°0 (±16.°0). Stars tracing {B}{POL} have the same mean distance as stars that do not trace {B}{POL}, but show weaker average polarizations consistent with a smaller column density of polarizing material. {B}{POL} is aligned with the ISMF traced by the IBEX Ribbon to within {7.6}-7.6+14.9 degrees. The variations in the polarization position angle directions derived from the data that best match {B}{POL} indicate a low level of <span class="hlt">magnetic</span> turbulence, ˜9° ± 1°. The direction of {B}{POL} is obtained after excluding polarization data tracing a separate <span class="hlt">magnetic</span> structure that appears to be associated with interstellar dust deflected around the heliosphere. The velocities of local interstellar clouds relative to the Local Standard of Rest (LSR) increase with the angles between the LSR velocities and {B}{POL}, indicating that the kinematics of local interstellar material is ordered by the ISMF. The Loop I superbubble that extends close to the Sun contains dust that reddens starlight and whose distance is determined by the color excess E(B - V) of starlight. Polarizations caused by grains aligned with respect to {B}{POL} are consistent with the location of the Sun in the rim of the Loop I superbubble. An angle of {76.8}-27.6+23.5 between {B}{POL} and the bulk LSR velocity the local interstellar material indicates a geometry that is consistent with an expanding superbubble. The efficiency of grain alignment in the local interstellar medium has been assessed using stars where both polarization data and hydrogen column density data are available. Nearby stars appear to have larger polarizations than expected based on reddened sightlines, which is consistent with previous results, but uncertainties are large. Optical polarization and color excess E(B - V) data indicate the presence of nearby interstellar dust in the BICEP2 field. Color excess E(B - V) indicates an optical extinction of AV > 0.6 in the BICEP2 field, while the polarization data indicate that AV > 0.09 mag. The IBEX Ribbon ISMF extends to the boundaries of the BICEP2 region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1236758-scanning-tunneling-spectroscopy-magnetic-atom-graphene-kondo-regime','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1236758-scanning-tunneling-spectroscopy-magnetic-atom-graphene-kondo-regime"><span id="translatedtitle">Scanning tunneling spectroscopy of a <span class="hlt">magnetic</span> <span class="hlt">atom</span> on graphene in the Kondo regime</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Zhuang, Huai -Bin; Sun, Qing -feng; Xie, X. C.</p> <p>2009-06-23</p> <p>In this study, the Kondo effect in the system consisting of a <span class="hlt">magnetic</span> adatom on the graphene is studied. By using the non-equilibrium Green function method with the slave-boson mean field approximation, the local density of state (LDOS) and the conductance are calculated. For a doped graphene, the Kondo phase is present at all time. Surprisingly, two kinds of Kondo regimes are revealed. But for the undoped graphene, the Kondo phase only exists if the adatom’s energy level is beyond a critical value. The conductance is similar to the LDOS, thus, the Kondo peak in the LDOS can be observedmore » with the scanning tunneling spectroscopy. In addition, in the presence of a direct coupling between the STM tip and the graphene, the conductance may be dramatically enhanced, depending on the coupling site.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20640184','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20640184"><span id="translatedtitle"><span class="hlt">Magnetic</span> circular dichroism in the ion yield of polarized chromium <span class="hlt">atoms</span> at the 2p edge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pruemper, G.; Viefhaus, J.; Becker, U.; Kroeger, S.; Mueller, R.; Zimmermann, P.; Martins, M.</p> <p>2003-09-01</p> <p>The effect of <span class="hlt">magnetic</span> dichroism in the partial and total ion yield of chromium, i.e., the absorption of polarized chromium vapor was observed in the gas phase. The measurements were performed at the 2p edge and at photon energies above the 2p edge. The structure of the dichroism at the 2p edge can be understood by including the coupling of the 2p hole with the 3d and 4s shells. Our experimental results for the dichroism at the 2p edge are similar to results of solid-state experiments. Implications for the sum rules used as a standard tool to calculate the spin and orbital momentum are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22054261','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22054261"><span id="translatedtitle">Structure and <span class="hlt">magnetic</span> properties of heterometallic coordination carboxylate polymers with cobalt and lithium <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Evstifeev, I. E.; Kiskin, M. A.; Bogomyakov, A. S.; Sidorov, A. A.; Novotortsev, V. M.; Eremenko, I. L.</p> <p>2011-09-15</p> <p>Reactions between lithium pivalate and cobalt coordination polymers [Co{sub 5}(OH{sub 2})(OH)(Piv){sub 9})L{sup 1}){sub 4}]{sub n} (I) and [Co{sub 2}(OH{sub 2})(Piv){sub 4}(L{sup 2}){sub 2}]{sub n} (II), where Piv-is the pivalate anion, L{sup 1} is pyrazine, and L{sup 2} is pyrimidine, result in new heterometallic polymers {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 1}){sub 2}]{sub 2}MeCN{r_brace}{sub n} (III), {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2})]{sub 0.5}MeCN{r_brace}{sub n} (IV), and [Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2}){sub 2}]{sub n} (V). The resulting compounds contain tetra-nuclear {l_brace}Li{sub 2}Co{sub 2}(Piv){sub 6}{r_brace} fragments connected by neutral bridging ligands (pyrazine or pyrimidine) into layer structures. Crystal structures III-V are determined, and the <span class="hlt">magnetic</span> properties of III and IV are studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93k5135V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93k5135V"><span id="translatedtitle"><span class="hlt">Warm</span> dense crystallography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valenza, Ryan A.; Seidler, Gerald T.</p> <p>2016-03-01</p> <p>The intense femtosecond-scale pulses from x-ray free electron lasers (XFELs) are able to create and interrogate interesting states of matter characterized by long-lived nonequilibrium semicore or core electron occupancies or by the heating of dense phases via the relaxation cascade initiated by the photoelectric effect. We address here the latter case of "<span class="hlt">warm</span> dense matter" (WDM) and investigate the observable consequences of x-ray heating of the electronic degrees of freedom in crystalline systems. We report temperature-dependent density functional theory calculations for the x-ray diffraction from crystalline LiF, graphite, diamond, and Be. We find testable, strong signatures of condensed-phase effects that emphasize the importance of wide-angle scattering to study nonequilibrium states. These results also suggest that the reorganization of the valence electron density at eV-scale temperatures presents a confounding factor to achieving <span class="hlt">atomic</span> resolution in macromolecular serial femtosecond crystallography (SFX) studies at XFELs, as performed under the "diffract before destroy" paradigm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhDT.......258O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhDT.......258O"><span id="translatedtitle">Chiral and <span class="hlt">magnetic</span> rotation in <span class="hlt">atomic</span> nuclei studied within self-consistent mean-field methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olbratowski, P.</p> <p>2004-07-01</p> <p>Currently, one application of the mean-field methods in nuclear physics is the investigation of exotic nuclear symmetries. This is related, in particular, to the study of nuclear rotation about an axis tilted with respect to the principal axes of the mass distribution in the Tilted-Axis Cranking (TAC) model. The present work presents one of the first TAC calculations performed within fully self-consistent methods. The Hartree-Fock method with the Skyrme effective two-body interaction has been used. A computer code has been developed that allows for the breaking of all spatial symmetries of the solution. As a first application, calculations for the <span class="hlt">magnetic</span> bands in 142Gd and for the chiral bands in 130Cs, 132La, 134Pr, and 136Pm have been carried out. The appearance of those bands is due to a new mechanism of breaking the spherical symmetry and to the spontaneous breaking of the chiral symmetry, respectively. The self-consistent solutions for 142Gd confirm the important role of the shears mechanism in generating the total angular momentum. However, the agreement with experimental data is not satisfactory, probably due to the lack of the pairing correlations in the calculations or to the possibly overestimated deformation. The results obtained for 132La constitute the first fully self-consistent proof that the nuclear rotation can attain a chiral character. It has been shown that the chiral rotation can only exist above a certain critical angular frequency. It has also been checked that the terms of the Skyrme mean field odd under the time reversal have no qualitative influence on the results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..93b2504S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..93b2504S"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field-induced electric quadrupole moments for relativistic hydrogenlike <span class="hlt">atoms</span>: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stefańska, Patrycja</p> <p>2016-02-01</p> <p>We consider a Dirac one-electron <span class="hlt">atom</span> placed in a weak, static, uniform <span class="hlt">magnetic</span> field. We show that, to the first order in the strength B of the external field, the only electric multipole moments, which are induced by the perturbation in the <span class="hlt">atom</span>, are those of an even order. Using the Sturmian expansion of the generalized Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B 30, 825 (1997), 10.1088/0953-4075/30/4/007; J. Phys. B 30, 2747 (1997), 10.1088/0953-4075/30/11/023], We derive a closed-form expression for the electric quadrupole moment induced in the <span class="hlt">atom</span> in an arbitrary discrete energy eigenstate. The result, which has the form of a double finite sum involving the generalized hypergeometric functions 3F2 of the unit argument, agrees with the earlier relativistic formula for that quantity, obtained by us for the ground state of the <span class="hlt">atom</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......394S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......394S"><span id="translatedtitle">On the electronic and <span class="hlt">magnetic</span> properties of nanostructures, solids and cold <span class="hlt">atomic</span> gases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sau, Jay Deep</p> <p></p> <p>In this work we calculate the properties of several condensed matter systems using a combination of empirical model Hamiltonian approaches and methods from computational condensed matter physics such as density functional theory and numerical solutions of the mean-field Gross-Pitaevskii equations. This work has been organized into 7 chapters as follows. (1) In the first chapter we motivate the discussion for the rest of the thesis and discuss the theoretical ideas that underly the work. (2) In the second chapter we discuss the approaches and approximations such as density functional theory and many-body perturbation theory that have been used in this research to make the many-electron problem a tractable one. (3) In the third chapter we discuss the application of density functional theory calculations to the analysis of scanning tunneling microscope (STM) images of boron nitride nanotubes. It is found experimentally and confirmed theoretically that the electric field of the STM can be used to lower the gap of the nanotube in a controllable fashion and also the modify the shape of the electronic states on the nanotube. (4) In the fourth chapter we extend the idea of modifying electronic properties of boron nitride nanotubes with an STM and apply the principle to carbon nanotube bundles. In this study a combination of density functional theory and model Hamiltonian calculations is used to derive a theoretical prediction where the application of an electric field through an STM can drive a transition of a nanotube bundle from a semiconductor to an excitonic system where the ground state is populated with a density of excitons that is tunable by the electric field strength. (5) In the fifth chapter we discuss another class of nanosystems, and focus on molecules on metallic substrates. These systems have been the subject of a large number of studies because of their technological relevance to solar-cells and molecular electronic devices. In this chapter we develop a technique to determine the level alignment and gaps of a molecule in the neighborhood of a substrate. We then test our method by quantitatively comparing the results of this method applied to the C 60 molecule on Au and Ag substrates to experimental scanning tunneling spectroscopy results on these systems. (6) In chapter six we move our focus to bulk systems and use a combination of density functional theory and empirical pseudopotential methods to study the transport properties of Ge-Sn alloy systems. Using the empirical pseudopotential method we find a combination of strain and alloying that turns Ge-Sn into a direct gap semiconductor with low electron and hole masses. The low effective masses implies an increased carrier mobility for the alloy. Using density functional theory calculations we calculate the effect of alloy scattering from Sn in Ge and show that even after taking into account substitutional disorder from alloy scattering Ge-Sn alloys are expected to exhibit higher mobilities than Ge. (7) In the final chapter we apply the combination of a model Hamiltonian and a computational solution of mean field equations that we have been applying to solid state systems to understand and predict the properties of ultra-cold spinor Bose Eintein Condensates. In this study we study the effect of how dipole-dipole interactions between spin-1 Rubidium <span class="hlt">atoms</span> can directly affect the dynamics of quantum noise induced domain formation and predict ways to directly observe the dipole-dipole interactions between 87Rb.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/1373978','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/1373978"><span id="translatedtitle">Matrix-assisted laser desorption using a fast-<span class="hlt">atom</span> bombardment ion source and a <span class="hlt">magnetic</span> mass spectrometer.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Annan, R S; Köchling, H J; Hill, J A; Biemann, K</p> <p>1992-04-01</p> <p>A conventional fast-<span class="hlt">atom</span> bombardment (FAB) ion source was used to achieve matrix-assisted laser desorption (MALD) in a high-mass, double-focusing, <span class="hlt">magnetic</span> mass spectrometer. The pulsed ion signals generated by irradiation of a mixture of sample and matrix (2,5-dihydroxybenzoic acid) with either a XeF excimer laser (353 nm) or a nitrogen laser (337 nm) were recorded with a focal-plane detector. A resolution (full-width at half maximum) of 4500 was achieved at m/z 1347.7 (the peptide substance P), 2500 for CsI cluster ions at m/z 10,005.7, and 1250 for the isotope cluster of the small protein cytochrome c (horse) [M+H]+ = m/z 12,360 (average). Sensitivity is demonstrated with 11 fmol of substance P. A survey scan is taken to locate the m/z of the sample molecular ion. The segment that contains the sample can then be integrated for a longer time to produce a better signal-to-noise ratio. In addition to higher sensitivity and lower matrix interference, the advantage of MALD over FAB is the former's lower susceptibility to the presence of salts, and competition between hydrophobic and hydrophilic components of a mixture. This feature is demonstrated by the complete MALD spectrum of a crude partial tryptic digest of sperm-whale apomyoglobin, containing 24 peptides, representing the entire sequence of this protein. PMID:1373978</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12513630','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12513630"><span id="translatedtitle">Hydrogen <span class="hlt">atom</span> in the presence of uniform <span class="hlt">magnetic</span> and quadrupolar electric fields: integrability, bifurcations, and chaotic behavior.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Iñarrea, M; Salas, J P; Lanchares, V</p> <p>2002-11-01</p> <p>We investigate the classical dynamics of a hydrogen <span class="hlt">atom</span> in the presence of uniform <span class="hlt">magnetic</span> and quadrupolar electric fields. After some reductions, the system is described by a two degree of freedom Hamiltonian depending on two parameters. On the one hand, it depends on the z component of the canonical angular momentum P(phi), which is an integral because the system is axially symmetric; and on the other it also depends on a parameter representing the relative field strengths. We note that this Hamiltonian is closely related to the one describing the generalized van der Waals interaction. We report three cases of integrability. The structure and evolution of the phase space are explored intensively by means of Poincaré surfaces of section when the parameters vary. In this sense, we find several bifurcations that strongly change the phase space structure. The chaotic behavior of the system is studied and three order-chaos transitions are found when the system passes through the integrable cases. Finally, the ionization mechanics is studied. PMID:12513630</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARF21013K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARF21013K"><span id="translatedtitle">Radiation pressure excitation of Low Temperature <span class="hlt">Atomic</span> Force & <span class="hlt">Magnetic</span> Force Microscope (LT-AFM/MFM) for Imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karci, Ozgur; Celik, Umit; Oral, Ahmet; NanoMagnetics Instruments Ltd. Team; Middle East Tech Univ Team</p> <p>2015-03-01</p> <p>We describe a novel method for excitation of <span class="hlt">Atomic</span> Force Microscope (AFM) cantilevers by means of radiation pressure for imaging in an AFM for the first time. Piezo excitation is the most common method for cantilever excitation, but it may cause spurious resonance peaks. A fiber optic interferometer with 1310 nm laser was used both to measure the deflection of cantilever and apply a force to the cantilever in a LT-AFM/MFM from Nano<span class="hlt">Magnetics</span> Instruments. The laser power was modulated at the cantilever`s resonance frequency by a digital Phase Lock Loop (PLL). The force exerted by the radiation pressure on a perfectly reflecting surface by a laser beam of power P is F = 2P/c. We typically modulate the laser beam by ~ 800 μW and obtain 10nm oscillation amplitude with Q ~ 8,000 at 2.5x10-4 mbar. The cantilever's stiffness can be accurately calibrated by using the radiation pressure. We have demonstrated performance of the radiation pressure excitation in AFM/MFM by imaging a hard disk sample between 4-300K and Abrikosov vortex lattice in BSCCO single crystal at 4K to for the first time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..401..816M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..401..816M"><span id="translatedtitle">The elastic, electronic and <span class="hlt">magnetism</span> structure of the MAl and M3Al (M=Fe and Ni) alloy with and without hydrogen <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mubarak, A. A.</p> <p>2016-03-01</p> <p>The energetic stability, electronic and <span class="hlt">magnetism</span> of the MAl, M3Al alloy (M=Fe, Ni) and variant surfaces of MAl (001) with and without hydrogen <span class="hlt">atoms</span> are investigated by utilizing DFT and GGA as the exchange-correlation potential. All presented alloys with and without the H <span class="hlt">atom</span> absorption is found elastically and thermodynamically stable. The calculated absorption energy shows that H is more energetically stable in the bridge and octahedral site in MAl and M3Al alloys, respectively. Hydrogen <span class="hlt">atoms</span> absorption is expanded and brittle the studied host alloys. The ability of absorption of H <span class="hlt">atom</span> at more than one site in the MAl alloy is found energetically and thermodynamically stable. The H adsorption on the variant surfaces of MAl (001) is predicted too. Fourfold and top sites are found more energetically stable to adsorbed the H <span class="hlt">atom</span> on the above surface layer of H/MAl-M and H/MAl-Al, respectively. The obvious changes are observed in the interlayer spacing for studied surfaces which yields to decrease the LDOS and <span class="hlt">magnetic</span> moments of the surface and subsurface layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22306329','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22306329"><span id="translatedtitle">Two Keggin-type heteropolytungstates with transition metal as a central <span class="hlt">atom</span>: Crystal structure and <span class="hlt">magnetic</span> study with 2D-IR correlation spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chai, Feng; Chen, YiPing; You, ZhuChai; Xia, ZeMin; Ge, SuZhi; Sun, YanQiong; Huang, BiHua</p> <p>2013-06-01</p> <p>Two Keggin-type heteropolytungstates, [Co(phen)₃]₃[CoW₁₂O₄₀]·9H₂O 1 (phen=1,10-phenanthroline) and [Fe(phen)₃]₂[FeW₁₂O₄₀]·H₃O·H₂O 2, have been synthesized via the hydrothermal technique and characterized by single crystal X-ray diffraction analyses, IR, XPS, TG analysis, UV–DRS, XRD, thermal-dependent and <span class="hlt">magnetic</span>-dependent 2D-COS IR (two-dimensional infrared correlation spectroscopy). Crystal structure analysis reveals that the polyanions in compound 1 are linked into 3D supramolecule through hydrogen bonding interactions between lattice water molecules and terminal oxygen <span class="hlt">atoms</span> of polyanion units, and [Co(phen)₃]²⁺ cations distributed in the polyanion framework with many hydrogen bonding interactions. The XPS spectra indicate that all the Co <span class="hlt">atoms</span> in 1 are +2 oxidation state, the Fe <span class="hlt">atoms</span> in 2 existing with +2 and +3 mixed oxidation states. - Graphical abstract: The <span class="hlt">magnetic</span>-dependent synchronous 2D correlation IR spectra of 1 (a), 2 (b) over 0–50 mT in the range of 600–1000 cm⁻¹, the obvious response indicate two Keggin polyanions skeleton susceptible to applied <span class="hlt">magnetic</span> field. Highlights: • Two Keggin-type heteropolytungstates with transition metal as a central <span class="hlt">atom</span> has been obtained. • Compound 1 forms into 3D supramolecular architecture through hydrogen bonding between water molecules and polyanions. • <span class="hlt">Magnetic</span>-dependent 2D-IR correlation spectroscopy was introduced to discuss the <span class="hlt">magnetism</span> of polyoxometalate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93r4404K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93r4404K"><span id="translatedtitle"><span class="hlt">Magnetic</span> ordering and exchange interactions in structural modifications of M n3Ga alloys: Interplay of frustration, <span class="hlt">atomic</span> order, and off-stoichiometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khmelevskyi, Sergii; Ruban, Andrei V.; Mohn, Peter</p> <p>2016-05-01</p> <p>Mn-Ga alloys close to the M n3Ga stoichiometry can be synthesized in three different crystal modifications: hexagonal, tetragonal, and face-centered cubic, both in bulk and in thin-film forms. The <span class="hlt">magnetic</span> ordering of these modifications is varying from noncollinear antiferromagnetic in the hexagonal case to ferrimagnetic order in the tetragonal one, whereas it is still unknown for the <span class="hlt">atomically</span> disordered fcc structure. Here we study the onset of <span class="hlt">magnetic</span> order at finite temperatures in these systems on a first-principles basis calculating the interatomic <span class="hlt">magnetic</span> exchange interactions in the high-temperature paramagnetic regime. We employ the disordered local moment formalism and the <span class="hlt">magnetic</span> force theorem within the framework of the local spin-density approximation and Monte Carlo simulations taking also the effects of <span class="hlt">atomic</span> disorder in fcc alloys into account. In particular we find the origin of the stabilization of the noncollinear 3 k structure in competition between antiferromagnetic inter- and in-plane couplings of frustrated kagome planes in hexagonal M n3Ga and predict the antiferromagnetic-1 collinear order due to frustration in fcc alloys. Special attention is paid to the effects of the off-stoichiometry and the consequences of <span class="hlt">atomic</span> disorder. We calculate the site-preference energy of Ga antisite <span class="hlt">atoms</span> in the tetragonal structures in the range of the compositions from M n3Ga to M n2Ga and slightly beyond and confirm the earlier explanation of the effect of <span class="hlt">magnetization</span> increase due to Ga preferentially occupying one of the Mn sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5257938','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5257938"><span id="translatedtitle">Construction and test results of a compact 0. 8 meter <span class="hlt">warm</span> bore 1. 5 Tesla high homogeneity superconducting <span class="hlt">magnet</span> for MR spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nenonen, S. ); Friman, E.; Ikkala, O. ); Islander, S. ); Seppala, H.; Pekola, J. ); Sariala, A. ); Collan, H.K. )</p> <p>1992-01-01</p> <p>a superconducting <span class="hlt">magnet</span> aimed at whole body MRI and spectroscopic studies was designed, constructed and tested. <span class="hlt">Magnet</span> was wound with a 2 mm diameter NbTi/Cu multifilamentary composite conductor. The design field was B{sub 0} = 1.5 T, the design value for field homogeneity {Delta}B/B{sub 0} - 0.1 ppm over a 20 cm diameter spherical volume, and the design value for the field stability dB{sub 0}/dt/B{sub 0} {le} 0.1 ppm/h. During construction of the <span class="hlt">magnet</span>, special emphasis was put into evaluating the winding accuracy which is attainable in practice. Dimensional measurements on the coil were compared with subsequent field measurements. The <span class="hlt">magnet</span> was designed to be fully self-protective in the event of a quench. The quench calculations were verified by test quench measurements. The <span class="hlt">magnet</span> was cooled by immersion in a 300 liter LHe-bath of an annular helium cryostat having an 0.8 m diameter GRP room temperature bore tube, with a 7 l/d LHE boil-off. In this paper constructional and design aspects are discussed and test results are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080023614','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080023614"><span id="translatedtitle">Actuated <span class="hlt">atomizer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)</p> <p>2008-01-01</p> <p>An actuated <span class="hlt">atomizer</span> is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated <span class="hlt">atomizer</span> includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a <span class="hlt">magnetic</span> field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the <span class="hlt">magnetic</span> field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the <span class="hlt">atomizer</span> from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the <span class="hlt">atomizer</span> to release <span class="hlt">atomized</span> fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the <span class="hlt">magnetic</span> field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016FBS....57...71S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016FBS....57...71S"><span id="translatedtitle">The Gaussian <span class="hlt">Atomic</span> Orbital Multiplied by a Field-Dependent Gauge Phase for the Hydrogen Molecular Ion in Non-aligned <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, Xuanyu; Li, Cun; Wang, Xiaofeng; Qiao, Haoxue</p> <p>2016-01-01</p> <p>We multiply the anisotropic Gaussian <span class="hlt">atomic</span> orbital by a field-dependent gauge phase to describe the wave function for the hydrogen molecular ion in non-aligned <span class="hlt">magnetic</span> fields. With the kind of basis set, the convergence of the total energy at the equilibrium distance for the 1 u state is much improved compared to the same <span class="hlt">atomic</span> orbital without the gauge phase. For 2.35 × 104 ≤ B ≤ 107 T, better total energies of the 1 u state at the corresponding equilibrium are obtained for the deviations 15°-90° of the <span class="hlt">magnetic</span> field relative to the molecular axis. The result also shows that, there is a transition of the equilibrium configuration from the vertical orientation to the parallel orientation with increasing field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029677&hterms=atomic+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Datomic%2Bstructure','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029677&hterms=atomic+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Datomic%2Bstructure"><span id="translatedtitle"><span class="hlt">Atomic</span> sulfur: Frequency measurement of the J = 0 left arrow 1 fine-structure transition at 56.3 microns by laser <span class="hlt">magnetic</span> resonance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, John M.; Evenson, Kenneth M.; Zink, Lyndon R.</p> <p>1994-01-01</p> <p>The J = 0 left arrow 1 fine-structure transition in <span class="hlt">atomic</span> sulfur (S I) in its ground (3)P state has been detected in the laboratory by far-infrared laser <span class="hlt">magnetic</span> resonance. The fine-structure interval has been measured accurately as 5,322,492.9 +/- 2.8 MHz which corresponds to a wavelength of 56.325572 +/- 0.000030 micrometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvL.116o7203A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvL.116o7203A"><span id="translatedtitle"><span class="hlt">Magnetism</span>, Spin Texture, and In-Gap States: <span class="hlt">Atomic</span> Specialization at the Surface of Oxygen-Deficient SrTiO3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Altmeyer, Michaela; Jeschke, Harald O.; Hijano-Cubelos, Oliver; Martins, Cyril; Lechermann, Frank; Koepernik, Klaus; Santander-Syro, Andrés F.; Rozenberg, Marcelo J.; Valentí, Roser; Gabay, Marc</p> <p>2016-04-01</p> <p>Motivated by recent spin- and angular-resolved photoemission (SARPES) measurements of the two-dimensional electronic states confined near the (001) surface of oxygen-deficient SrTiO3, we explore their spin structure by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic nonmagnetic DFT calculations display Rashba-like spin winding with a splitting of a few meV and when surface <span class="hlt">magnetism</span> on the Ti ions is included, bands become spin-split with an energy difference ˜100 meV at the Γ point, consistent with SARPES findings. While <span class="hlt">magnetism</span> tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures. Furthermore, we observe an <span class="hlt">atomic</span> specialization phenomenon, namely, two types of electronic contributions: one is from Ti <span class="hlt">atoms</span> neighboring the oxygen vacancies that acquire rather large <span class="hlt">magnetic</span> moments and mostly create in-gap states; another comes from the partly polarized t2 g itinerant electrons of Ti <span class="hlt">atoms</span> lying further away from the oxygen vacancy, which form the two-dimensional electron system and are responsible for the Rashba spin winding and the spin splitting at the Fermi surface.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27127984','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27127984"><span id="translatedtitle"><span class="hlt">Magnetism</span>, Spin Texture, and In-Gap States: <span class="hlt">Atomic</span> Specialization at the Surface of Oxygen-Deficient SrTiO_{3}.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Altmeyer, Michaela; Jeschke, Harald O; Hijano-Cubelos, Oliver; Martins, Cyril; Lechermann, Frank; Koepernik, Klaus; Santander-Syro, Andrés F; Rozenberg, Marcelo J; Valentí, Roser; Gabay, Marc</p> <p>2016-04-15</p> <p>Motivated by recent spin- and angular-resolved photoemission (SARPES) measurements of the two-dimensional electronic states confined near the (001) surface of oxygen-deficient SrTiO_{3}, we explore their spin structure by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic nonmagnetic DFT calculations display Rashba-like spin winding with a splitting of a few meV and when surface <span class="hlt">magnetism</span> on the Ti ions is included, bands become spin-split with an energy difference ∼100  meV at the Γ point, consistent with SARPES findings. While <span class="hlt">magnetism</span> tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures. Furthermore, we observe an <span class="hlt">atomic</span> specialization phenomenon, namely, two types of electronic contributions: one is from Ti <span class="hlt">atoms</span> neighboring the oxygen vacancies that acquire rather large <span class="hlt">magnetic</span> moments and mostly create in-gap states; another comes from the partly polarized t_{2g} itinerant electrons of Ti <span class="hlt">atoms</span> lying further away from the oxygen vacancy, which form the two-dimensional electron system and are responsible for the Rashba spin winding and the spin splitting at the Fermi surface. PMID:27127984</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyE...65...24Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyE...65...24Z"><span id="translatedtitle">Structure, electronic and <span class="hlt">magnetic</span> properties of hexagonal boron nitride sheets doped by 5d transition metal <span class="hlt">atoms</span>: First-principles calculations and molecular orbital analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Zhaofu; Geng, Zhaohui; Cai, Danyun; Pan, Tongxi; Chen, Yixin; Dong, Liyuan; Zhou, Tiege</p> <p>2015-01-01</p> <p>A first-principles calculation based on density functional theory is carried out to reveal the geometry, electronic structures and <span class="hlt">magnetic</span> properties of hexagonal boron nitride sheets (h-BNSs) doped by 5d transitional mental <span class="hlt">atoms</span> (Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au and Hg) at boron-site (B5d) and nitrogen-site (N5d). Results of pure h-BNS, h-BNS with B vacancy (VB) and N vacancy (VN) are also given for comparison. It is shown that all the h-BNSs doped with 5d <span class="hlt">atoms</span> possess a C3v local symmetry except for NLu and NHg which have a clear deviation. For the same 5d dopant, the binding energy of B5d is larger than that of N5d, which indicates the substitution of a 5d <span class="hlt">atom</span> for B is preferred. The total densities of states are presented, where impurity energy levels exist. Besides, the total <span class="hlt">magnetic</span> moments (TMMs) change regularly with the increment of the 5d <span class="hlt">atomic</span> number. Theoretical analyses by molecular orbital under C3v symmetry explain the impurity energy levels and TMMs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/943848','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/943848"><span id="translatedtitle">Neutral <span class="hlt">atom</span> traps.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pack, Michael Vern</p> <p>2008-12-01</p> <p>This report describes progress in designing a neutral <span class="hlt">atom</span> trap capable of trapping sub millikelvin <span class="hlt">atom</span> in a <span class="hlt">magnetic</span> trap and shuttling the <span class="hlt">atoms</span> across the <span class="hlt">atom</span> chip from a collection area to an optical cavity. The numerical simulation and <span class="hlt">atom</span> chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JChPh.137j4302T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JChPh.137j4302T"><span id="translatedtitle">Cold collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in a <span class="hlt">magnetic</span> field: An ab initio study of He + CH2(X~) collisions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tscherbul, T. V.; Grinev, T. A.; Yu, H.-G.; Dalgarno, A.; Kłos, Jacek; Ma, Lifang; Alexander, Millard H.</p> <p>2012-09-01</p> <p>We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state <span class="hlt">atoms</span> in the presence of an external <span class="hlt">magnetic</span> field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wave function. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH_2(tilde{X}^3B_1)] with He <span class="hlt">atoms</span>. To this end, two accurate three-dimensional potential energy surfaces (PESs) of the He-CH_2(tilde{X}^3B_1) complex are developed using the state-of-the-art coupled-cluster method including single and double excitations along with a perturbative correction for triple excitations and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH2, CHD, and CD2 molecules with He <span class="hlt">atoms</span> occurs at a much slower rate than elastic scattering over a large range of temperatures (1 μK-1 K) and <span class="hlt">magnetic</span> fields (0.01-1 T), suggesting excellent prospects for cryogenic helium buffer-gas cooling of ground-state ortho-CH_2(tilde{X}^3B_1) molecules in a <span class="hlt">magnetic</span> trap. Furthermore, we find that ortho-CH2 undergoes collision-induced spin relaxation much more slowly than para-CH2, which indicates that <span class="hlt">magnetic</span> trapping can be used to separate nuclear spin isomers of open-shell polyatomic molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015aska.confE.110R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015aska.confE.110R"><span id="translatedtitle">Measuring <span class="hlt">Magnetic</span> Fields Near and Far with the SKA via the Zeeman Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robishaw, T.; Green, J.; Surcis, G.; Vlemmings, W. H. T.; Richards, A. M. S.; Etoka, S.; Bourke, T.; Fish, V.; Gray, M. D.; Imai, H.; Kramer, B.; McBride, J.; Momjian, E.; Sarma, A. P.; Zijlstra, A. A.</p> <p></p> <p>The measurement of Zeeman splitting in spectral lines---both in emission and absorption---can provide direct estimates of the <span class="hlt">magnetic</span> field strength and direction in <span class="hlt">atomic</span> and molecular clouds, both in our own Milky Way and in external galaxies. This method will probe the <span class="hlt">magnetic</span> field in the <span class="hlt">warm</span> and cold neutral components of the interstellar medium, providing a complement to the extensive SKA Faraday studies planning to probe the field in the ionized components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26571041','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26571041"><span id="translatedtitle">Investigation of the <span class="hlt">magnetic</span> dipole field at the <span class="hlt">atomic</span> scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Guoqing; Ye, Xiao-shan; Zeng, Xianghua; Wu, Bing; Clark, W G</p> <p>2016-01-13</p> <p>We report <span class="hlt">magnetic</span> dipole field investigation at the <span class="hlt">atomic</span> scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and (7)Li-NMR spectroscopy measurements with an externally applied <span class="hlt">magnetic</span> field B 0  =  9 T. We find that the <span class="hlt">magnetic</span> dipole field component ([Formula: see text]) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle [Formula: see text], while the [Formula: see text] maximum is at [Formula: see text] when B 0 is applied perpendicular to b ([Formula: see text]), where [Formula: see text] represents the direction of [Formula: see text]. Further estimation indicates that [Formula: see text] has a maximum value of 0.35 G at B 0  =  9 T. By minimizing the potential <span class="hlt">magnetic</span> contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the <span class="hlt">magnetic</span> dipole field component [Formula: see text] is  ∼0, the behavior of the electron charge statics is exhibited. This work demonstrates that the <span class="hlt">magnetic</span> dipole field of the Mo electrons is the dominant source of the local <span class="hlt">magnetic</span> fields at the Li site, and suggests that the unknown metal-'insulator' crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and <span class="hlt">magnetic</span> field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material. PMID:26571041</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPCM...28a5003W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPCM...28a5003W"><span id="translatedtitle">Investigation of the <span class="hlt">magnetic</span> dipole field at the <span class="hlt">atomic</span> scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Guoqing; Ye, Xiao-shan; Zeng, Xianghua; Wu, Bing; Clark, W. G.</p> <p>2016-01-01</p> <p>We report <span class="hlt">magnetic</span> dipole field investigation at the <span class="hlt">atomic</span> scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and 7Li-NMR spectroscopy measurements with an externally applied <span class="hlt">magnetic</span> field B 0??=??9 T. We find that the <span class="hlt">magnetic</span> dipole field component (B\\parallel\\text{dip} ) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle ? =+{{52.5}\\circ} , while the B\\parallel\\text{dip} maximum is at ? =+{{142.5}\\circ} when B 0 is applied perpendicular to b ({{B}0}\\bot b ), where ? ={{0}\\circ} represents the direction of {{B}0}\\parallel c . Further estimation indicates that B\\parallel\\text{dip} has a maximum value of 0.35 G at B 0??=??9 T. By minimizing the potential <span class="hlt">magnetic</span> contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the <span class="hlt">magnetic</span> dipole field component B\\parallel\\text{dip} is???0, the behavior of the electron charge statics is exhibited. This work demonstrates that the <span class="hlt">magnetic</span> dipole field of the Mo electrons is the dominant source of the local <span class="hlt">magnetic</span> fields at the Li site, and suggests that the unknown metal-insulator crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and <span class="hlt">magnetic</span> field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/46040','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/46040"><span id="translatedtitle">Global <span class="hlt">warming</span> elucidated</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shen, S.</p> <p>1995-03-01</p> <p>The meaning of global <span class="hlt">warming</span> and its relevance to everyday life is explained. Simple thermodynamics is used to predict an oscillatory nature of the change in climate due to global <span class="hlt">warming</span>. Global <span class="hlt">warming</span> causes extreme events and bad weather in the near term. In the long term it may cause the earth to transition to another equilibrium state through many oscillation in climatic patterns. The magnitudes of these oscillations could easily exceed the difference between the end points. The author further explains why many no longer fully understands the nature and magnitudes of common phenomena such as storms and wind speeds because of these oscillations, and the absorptive properties of clouds. The author links the increase in duration of the El Nino to global <span class="hlt">warming</span>, and further predicts public health risks as the earth transitions to another equilibrium state in its young history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000726"><span id="translatedtitle">Reconciling <span class="hlt">Warming</span> Trends</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, Gavin A.; Shindell, Drew T.; Tsigaridis, Konstantinos</p> <p>2014-01-01</p> <p>Climate models projected stronger <span class="hlt">warming</span> over the past 15 years than has been seen in observations. Conspiring factors of errors in volcanic and solar inputs, representations of aerosols, and El NiNo evolution, may explain most of the discrepancy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=dinosaur&pg=4&id=EJ658270','ERIC'); return false;" href="http://eric.ed.gov/?q=dinosaur&pg=4&id=EJ658270"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Dinosaurs.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mannlein, Sally</p> <p>2001-01-01</p> <p>Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of <span class="hlt">warm</span> and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030005428','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030005428"><span id="translatedtitle"><span class="hlt">Warm</span> Hands and Feet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1976-01-01</p> <p>Comfort Products, Inc. was responsible for the cold weather glove and thermal boots, adapted from a spacesuit design that kept astronauts <span class="hlt">warm</span> or cool in the temperature extremes of the Apollo Moon Mission. Gloves and boots are thermally heated. Batteries are worn inside wrist of glove or sealed in sole of skiboot and are rechargeable hundreds of times. They operate flexible resistance circuit which is turned on periodically when wearer wants to be <span class="hlt">warm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CoPhC.180..302E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CoPhC.180..302E"><span id="translatedtitle">A fast parallel code for calculating energies and oscillator strengths of many-electron <span class="hlt">atoms</span> at neutron star <span class="hlt">magnetic</span> field strengths in adiabatic approximation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engel, D.; Klews, M.; Wunner, G.</p> <p>2009-02-01</p> <p>We have developed a new method for the fast computation of wavelengths and oscillator strengths for medium-Z <span class="hlt">atoms</span> and ions, up to iron, at neutron star <span class="hlt">magnetic</span> field strengths. The method is a parallelized Hartree-Fock approach in adiabatic approximation based on finite-element and B-spline techniques. It turns out that typically 15-20 finite elements are sufficient to calculate energies to within a relative accuracy of 10-5 in 4 or 5 iteration steps using B-splines of 6th order, with parallelization speed-ups of 20 on a 26-processor machine. Results have been obtained for the energies of the ground states and excited levels and for the transition strengths of astrophysically relevant <span class="hlt">atoms</span> and ions in the range Z=2…26 in different ionization stages. Catalogue identifier: AECC_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECC_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3845 No. of bytes in distributed program, including test data, etc.: 27 989 Distribution format: tar.gz Programming language: MPI/Fortran 95 and Python Computer: Cluster of 1-26 HP Compaq dc5750 Operating system: Fedora 7 Has the code been vectorised or parallelized?: Yes RAM: 1 GByte Classification: 2.1 External routines: MPI/GFortran, LAPACK, PyLab/Matplotlib Nature of problem: Calculations of synthetic spectra [1] of strongly <span class="hlt">magnetized</span> neutron stars are bedevilled by the lack of data for <span class="hlt">atoms</span> in intense <span class="hlt">magnetic</span> fields. While the behaviour of hydrogen and helium has been investigated in detail (see, e.g., [2]), complete and reliable data for heavier elements, in particular iron, are still missing. Since neutron stars are formed by the collapse of the iron cores of massive stars, it may be assumed that their atmospheres contain an iron plasma. Our objective is to fill the gap and to provide a program which allows users to calculate as comprehensively as possible energies, wavelengths, and oscillator strengths of medium-Z <span class="hlt">atoms</span> and ions up to Z=26 in neutron star <span class="hlt">magnetic</span> field strengths. Obviously, the method for achieving this goal must be highly efficient since for the calculation of synthetic spectra data of many thousands or even millions of <span class="hlt">atomic</span> transitions may be required. Solution method: As in previous work on the problem (cf. [3,7]) we exploit the fact that a strong <span class="hlt">magnetic</span> field results in an approximate decoupling of the dynamics of the electrons parallel and perpendicular to the field. In this adiabatic approximation the single-particle wave functions take the form: ψ(ρ,φ,z)=ϕ(ρ,φ)ṡP(z), where ϕ(ρ,φ) are Landau wave functions, describing the (fast) motion perpendicular to the field, and the P(z) are the longitudinal wave functions, describing the (slow) bound motion along the direction of the field. The spins of the electrons are all aligned antiparallel to the <span class="hlt">magnetic</span> field and need not be accounted for explicitly. The total N-electron wave function is constructed as a Slater determinant of the single-particle wave functions, and the unknown longitudinal wave functions are determined from the Hartree-Fock equations, which follow from inserting the total N-electron wave function into Schrödinger's variational principle for the total energy. The novel feature of our approach [8] is to use finite-element and B-spline techniques to solve the Hartree-Fock equations for <span class="hlt">atoms</span> in strong <span class="hlt">magnetic</span> fields. This is accomplished through the following steps: 1) decomposition of the z-axis into finite elements with quadratically widening element borders; 2) sixth-order B-spline expansion of the single-particle wave functions on the individual finite elements; 3) formulation of the variational principle equivalent to the Hartree-Fock equations in terms of the expansion coefficients. This leads to a simple system of linear equations for the expansion coefficients, which is solved numerically, and, since the direct and exchange interaction potential terms depend on the wave functions, in a self consistent way. The iteration procedure is initialized by distributing the electrons on <span class="hlt">magnetic</span> sublevels according to the level scheme of the hydrogen <span class="hlt">atom</span> in intense <span class="hlt">magnetic</span> fields. To speed up the calculations, the code is parallelized. The parallelization strategy is: a) each processor calculates one or several electrons, depending on the total number of processors, b) single-particle wave functions are broadcast from each processor to every other processor. As the coefficient vectors in the B-spline basis are small (dim≈20-25), there is only little communication between the nodes. Typical speedups by a factor of 20 are obtained on a 26-processor cluster of HP Compaq dc57750. Running time: The test runs provided only require a few seconds using 2 processors. References: [1] K. Werner, S. Dreizler, The classical stellar atmosphere problem, in: H. Riffert, K. Werner (Eds.), Computational Astrophysics, Computational and Applied Mathematics, Elsevier, 1998. [2] H. Ruder, G. Wunner, H. Herold, F. Geyer, <span class="hlt">Atoms</span> in Strong <span class="hlt">Magnetic</span> Fields, Springer, Heidelberg, 1994. [3] P.B. Jones, Mon. Not. R. Astron. Soc. 216 (1985) 503. [4] D. Neuhauser, K. Langanke, S.E. Koonin, Phys. Rev. A 33 (1986) 2084. [5] M.C. Miller, D. Neuhauser, Mon. Not. R. Astron. Soc. 253 (1991) 107. [6] M. Rajagopal, R.W. Romani, M.C. Miller, Astrophys. J. 479 (1997) 347. [7] K. Mori, C.J. Hailey, Astrophys. J. 564 (2002) 914. [8] M. Klews, Discretization methods for the investigation of <span class="hlt">atoms</span> in time dependent electric fields, and in extremely strong <span class="hlt">magnetic</span> fields (in German), Doctoral Thesis, University of Tübingen, 2003, http://www.theo1.physik.unistuttgart. de/forschung/sfb382a15/klews2003.ps.gz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JAP...113j3908N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JAP...113j3908N"><span id="translatedtitle">Surface morphology and <span class="hlt">atomic</span> structure of thin layers of Fe3Si on GaAs(001) and their <span class="hlt">magnetic</span> properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noor, S.; Barsukov, I.; Özkan, M. S.; Elbers, L.; Melnichak, N.; Lindner, J.; Farle, M.; Köhler, U.</p> <p>2013-03-01</p> <p>The structural and <span class="hlt">magnetic</span> properties of ultrathin near-stoichiometric Fe3Si layers on GaAs(001) are investigated after using scanning tunneling microscopy (STM) analysis to optimize the deposition process. This includes <span class="hlt">atomic</span> resolution imaging of the surface as measured by STM revealing the <span class="hlt">atomic</span> ordering and characteristic defects in the topmost layers. Emphasis is laid on connections between the layer morphology and its <span class="hlt">magnetic</span> properties, which are analysed by in situ MOKE, FMR, and SQUID magnetometry. Upon nucleation, the Fe3Si islands behave like superparamagnetic nanoparticles where we find a quantitative agreement between the size of the nanoparticles and their superspin. At higher coverage, the Fe3Si layers show ferromagnetic behaviour. Here, we investigate the superposition of the magnetocrystalline and the uniaxial anisotropies where the latter can be excluded to be caused by shape anisotropy. Furthermore, an unexpected increase of the <span class="hlt">magnetic</span> moment towards low coverage can be observed which apart from an increased orbital moment can be attributed to an increased step density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvB..86u4205L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvB..86u4205L"><span id="translatedtitle">Role of <span class="hlt">magnetic</span> and <span class="hlt">atomic</span> ordering in the martensitic transformation of Ni-Mn-In from a first-principles study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Chun-Mei; Luo, Hu-Bin; Hu, Qing-Miao; Yang, Rui; Johansson, Börje; Vitos, Levente</p> <p>2012-12-01</p> <p>The composition-dependent lattice parameters, crystal structure, elastic properties, <span class="hlt">magnetic</span> moment, and electronic structure of Ni2Mn1+xIn1-x (0≤x≤0.6) are studied by using first-principles calculations. It is shown that the martensitic phase transition (MPT) from cubic L21 to tetragonal L10 accompanies the MnMn-MnIn ferromagnetic (FM) to antiferromagnetic (AFM) transition, at around the critical composition x=0.32, in agreement with the experimental measurement. The Mn-In <span class="hlt">atomic</span> disorder leads to decreasing stability of the martensite relative to the austenite, which depresses the MPT. The shear elastic constant C' of the parent phase first decreases slightly with increasing x and then remains almost unchanged above x=0.32, indicating C' alone cannot account for the increase of the MPT temperature with x. The total <span class="hlt">magnetic</span> moments for the L21 phase are in good agreement with those determined by experiments, whereas for the L10 phase they are slightly larger than the experimental data due to the possible Mn-In <span class="hlt">atomic</span> disorder in the sample. The calculated density of states demonstrate that the covalent bonding between the minority spin states of Ni and In plays an important role in both the <span class="hlt">magnetic</span> and structural stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JMMM..156..211B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JMMM..156..211B"><span id="translatedtitle">Variations in the <span class="hlt">magnetic</span> properties of ultrathin Co films due to the adsorption of non-<span class="hlt">magnetic</span> metal <span class="hlt">atoms</span> at the Co/vacuum interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buckley, M. E.; Hope, S.; Schumann, F. O.; Bland, J. A. C.</p> <p>1996-04-01</p> <p>The <span class="hlt">magnetic</span> properties of ultrathin Co/Cu films are strongly dependent on the nature of the interfaces. Using the magneto-optical Kerr effect, we report drastic effects due to the adsorption of sub-monolayer quantities of non-<span class="hlt">magnetic</span> metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069827','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069827"><span id="translatedtitle">Existence and stability of alternative ion-acoustic solitary wave solution of the combined MKdV-KdV-ZK equation in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.</p> <p>2007-09-15</p> <p>The purpose of this paper is to present the recent work of Das et al. [J. Plasma Phys. 72, 587 (2006)] on the existence and stability of the alternative solitary wave solution of fixed width of the combined MKdV-KdV-ZK (Modified Korteweg-de Vries-Korteweg-de Vries-Zakharov-Kuznetsov) equation for the ion-acoustic wave in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions in a more generalized form. Here we derive the alternative solitary wave solution of variable width instead of fixed width of the combined MKdV-KdV-ZK equation along with the condition for its existence and find that this solution assumes the sech profile of the MKdV-ZK (Modified Korteweg-de Vries-Zakharov-Kuznetsov) equation, when the coefficient of the nonlinear term of the KdV-ZK (Korteweg-de Vries-Zakharov-Kuznetsov) equation tends to zero. The three-dimensional stability analysis of the alternative solitary wave solution of variable width of the combined MKdV-KdV-ZK equation shows that the instability condition and the first order growth rate of instability are exactly the same as those of the solitary wave solution (the sech profile) of the MKdV-ZK equation, when the coefficient of the nonlinear term of the KdV-ZK equation tends to zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JPlPh..72..587D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JPlPh..72..587D"><span id="translatedtitle">Stability of an alternative solitary-wave solution of an ion-acoustic wave obtained from the MKdV KdV ZK equation in <span class="hlt">magnetized</span> non-thermal plasma consisting of <span class="hlt">warm</span> adiabatic ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.</p> <p></p> <p>The Korteweg de Varies Zakharov Kuznetsov (KdV ZK) equation describes the behaviour of long-wavelength weakly nonlinear ion-acoustic waves propagating obliquely to an external <span class="hlt">magnetic</span> field in a non-thermal plasma consisting of <span class="hlt">warm</span> adiabatic ions. When the coefficient of the nonlinear term of this equation vanishes, the nonlinear behaviour of ion-acoustic wave is described by a modified KdV ZK (MKdV ZK) equation. A combined MKdV KdV ZK equation more efficiently describes the nonlinear behaviour of ion-acoustic waves at points in the neighbourhood of the curve in the parametric plane along which the coefficient of the nonlinear term of the KdV ZK equation vanishes. This combined MKdV KdV ZK equation admits both double-layer and alternative solitary-wave solutions having profile different from sech(2) or sech. In this paper the three-dimensional stability of the alternative solitary-wave solution having profile different from sech(2) or sech has been investigated by the recently developed multiple-scale perturbation expansion method of Allen and Rowlands. The instability condition and the growth rate of instability have been derived at the lowest order. The correct expression of the growth rate of instability at the lowest order has been obtained for a limiting case and the stability analysis has been carried out numerically from our model as presented in this paper for arbitrary values of the parameters involved in the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhPl...14i2304D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhPl...14i2304D"><span id="translatedtitle">Existence and stability of alternative ion-acoustic solitary wave solution of the combined MKdV-KdV-ZK equation in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Das, Jayasree; Bandyopadhyay, Anup; Das, K. P.</p> <p>2007-09-01</p> <p>The purpose of this paper is to present the recent work of Das et al. [J. Plasma Phys. 72, 587 (2006)] on the existence and stability of the alternative solitary wave solution of fixed width of the combined MKdV-KdV-ZK (Modified Korteweg-de Vries-Korteweg-de Vries-Zakharov-Kuznetsov) equation for the ion-acoustic wave in a <span class="hlt">magnetized</span> nonthermal plasma consisting of <span class="hlt">warm</span> adiabatic ions in a more generalized form. Here we derive the alternative solitary wave solution of variable width instead of fixed width of the combined MKdV-KdV-ZK equation along with the condition for its existence and find that this solution assumes the sech profile of the MKdV-ZK (Modified Korteweg-de Vries-Zakharov-Kuznetsov) equation, when the coefficient of the nonlinear term of the KdV-ZK (Korteweg-de Vries-Zakharov-Kuznetsov) equation tends to zero. The three-dimensional stability analysis of the alternative solitary wave solution of variable width of the combined MKdV-KdV-ZK equation shows that the instability condition and the first order growth rate of instability are exactly the same as those of the solitary wave solution (the sech profile) of the MKdV-ZK equation, when the coefficient of the nonlinear term of the KdV-ZK equation tends to zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/245289','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/245289"><span id="translatedtitle"><span class="hlt">Warm</span> up to the idea: Global <span class="hlt">warming</span> is here</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lynch, C.F.</p> <p>1996-07-01</p> <p>This article summarizes recent information about global <span class="hlt">warming</span> as well as the history of greenhouse gas emissions which have lead to more and more evidence of global <span class="hlt">warming</span>. The primary source detailed is the second major study report on global <span class="hlt">warming</span> by the Intergovernmental Panel on climate change. Along with comments about the environmental effects of global <span class="hlt">warming</span> such as coastline submersion, the economic, social and political aspects of alleviating greenhouse emissions and the threat of global <span class="hlt">warming</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/153561','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/153561"><span id="translatedtitle">Long range global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rolle, K.C.; Pulkrabek, W.W.; Fiedler, R.A.</p> <p>1995-12-31</p> <p>This paper explores one of the causes of global <span class="hlt">warming</span> that is often overlooked, the direct heating of the environment by engineering systems. Most research and studies of global <span class="hlt">warming</span> concentrate on the modification that is occurring to atmospheric air as a result of pollution gases being added by various systems; i.e., refrigerants, nitrogen oxides, ozone, hydrocarbons, halon, and others. This modification affects the thermal radiation balance between earth, sun and space, resulting in a decrease of radiation outflow and a slow rise in the earth`s steady state temperature. For this reason the solution to the problem is perceived as one of cleaning up the processes and effluents that are discharged into the environment. In this paper arguments are presented that suggest, that there is a far more serious cause for global <span class="hlt">warming</span> that will manifest itself in the next two or three centuries; direct heating from the exponential growth of energy usage by humankind. Because this is a minor contributor to the global <span class="hlt">warming</span> problem at present, it is overlooked or ignored. Energy use from the combustion of fuels and from the output of nuclear reactions eventually is manifest as <span class="hlt">warming</span> of the surroundings. Thus, as energy is used at an ever increasing rate the consequent global <span class="hlt">warming</span> also increases at an ever increasing rate. Eventually this rate will become equal to a few percent of solar radiation. When this happens the earth`s temperature will have risen by several degrees with catastrophic results. The trends in world energy use are reviewed and some mathematical models are presented to suggest future scenarios. These models can be used to predict when the global <span class="hlt">warming</span> problem will become undeniably apparent, when it will become critical, and when it will become catastrophic.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6914531','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6914531"><span id="translatedtitle">Global <span class="hlt">warming</span> on trial</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Broeker, W.S.</p> <p>1992-04-01</p> <p>Jim Hansen, a climatologist at NASA's Goddard Space Institute, is convinced that the earth's temperature is rising and places the blame on the buildup of greenhouse gases in the atmosphere. Unconvinced, John Sununu, former White House chief of staff, doubts that the <span class="hlt">warming</span> will be great enough to produce serious threat and fears that measures to reduce the emissions would throw a wrench into the gears that drive the Unites States' troubled economy. During his three years at the White House, Sununu's view prevailed, and although his role in the debate has diminished, others continue to cast doubt on the reality of global <span class="hlt">warming</span>. A new lobbying group called the Climate Council has been created to do just this. Burning fossil fuels is not the only problem; a fifth of emissions of carbon dioxide now come from clearing and burning forests. Scientists are also tracking a host of other greenhouse gases that emanate from a variety of human activities; the <span class="hlt">warming</span> effect of methane, chlorofluorocarbons and nitrous oxide combined equals that of carbon dioxide. Although the current <span class="hlt">warming</span> from these gases may be difficult to detect against the background noise of natural climate variation, most climatologists are certain that as the gases continue to accumulate, increases in the earth's temperature will become evident even to skeptics. If the reality of global <span class="hlt">warming</span> were put on trial, each side would have trouble making its case. Jim Hansen's side could not prove beyond a reasonable doubt that carbon dioxide and other greenhouse gases have <span class="hlt">warmed</span> the planet. But neither could John Sununu's side prove beyond a reasonable doubt that the <span class="hlt">warming</span> expected from greenhouse gases has not occurred. To see why each side would have difficulty proving its case, this article reviews the arguments that might be presented in such a hearing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/868364','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/868364"><span id="translatedtitle"><span class="hlt">Atomizing</span> nozzle and process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.</p> <p>1992-06-30</p> <p>High pressure <span class="hlt">atomizing</span> nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt <span class="hlt">atomization</span>. The <span class="hlt">atomizing</span> nozzle is especially useful in <span class="hlt">atomizing</span> rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/868862','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/868862"><span id="translatedtitle"><span class="hlt">Atomizing</span> nozzle and process</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.</p> <p>1993-07-20</p> <p>High pressure <span class="hlt">atomizing</span> nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt <span class="hlt">atomization</span>. The <span class="hlt">atomizing</span> nozzle is especially useful in <span class="hlt">atomizing</span> rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OptL...39.2270S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OptL...39.2270S"><span id="translatedtitle">Saturated-absorption spectroscopy revisited: <span class="hlt">atomic</span> transitions in strong <span class="hlt">magnetic</span> fields (>20 mT) with a micrometer-thin cell</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sargsyan, A.; Tonoyan, A.; Mirzoyan, R.; Sarkisyan, D.; Wojciechowski, A. M.; Stabrawa, A.; Gawlik, W.</p> <p>2014-04-01</p> <p>The existence of cross-over resonances makes saturated-absorption spectra very complicated when external <span class="hlt">magnetic</span> field B is applied. It is demonstrated for the first time that the use of micrometric-thin cells (MTC, $L\\approx40\\,\\mu$m) allows application of SA for quantitative studies of frequency splittings and shifts of the Rb <span class="hlt">atomic</span> transitions in a wide range of external <span class="hlt">magnetic</span> fields, from 0.2 up to 6 kG (20-600 mT). We compare the SA spectra obtained with the MTC with those obtained with other techniques, and present applications for optical magnetometry with micrometer spatial resolution and a broadly tunable optical frequency reference.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22395714','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22395714"><span id="translatedtitle">Inhomogeneous broadening of optically detected <span class="hlt">magnetic</span> resonance of the ensembles of nitrogen-vacancy centers in diamond by interstitial carbon <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Levchenko, A. O. Vasil'ev, V. V.; Zibrov, S. A.; Zibrov, A. S.; Sivak, A. V.; Fedotov, I. V.</p> <p>2015-03-09</p> <p>We study the impact of the negatively charged nitrogen-vacancy (NV{sup –}) center density on the lattice strain resulting in the splitting of the optically detected <span class="hlt">magnetic</span> resonance of HPHT diamond. A simple model, taking into account the presence of the interstitial carbon <span class="hlt">atoms</span>, acting like a wedge force on the crystal lattice, explains the broadening and splitting of the optically detected <span class="hlt">magnetic</span> resonance of the ensemble of NV{sup –} centers at densities within the range of 10{sup 13} ÷ 10{sup 14 }cm{sup −3}. This model uses a complete generalized spin Hamiltonian, takes into account the strain-effect of each center in the ensemble and gives good agreement with experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25159398','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25159398"><span id="translatedtitle">Polyelectrolyte multilayers on <span class="hlt">magnetic</span> silica as a new sorbent for the separation of trace copper in food samples and determination by flame <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiang, Guoqiang; Ma, Yulong; Jiang, Xiuming; Mao, Pu</p> <p>2014-12-01</p> <p>A novel <span class="hlt">magnetic</span> silica sorbent with polyelectrolyte multilayers (PEMs) on its surface was prepared, and the sorbent was used for the <span class="hlt">magnetic</span> solid phase extraction (MSPE) of trace Cu(2+) in drinking water with flame <span class="hlt">atomic</span> absorption spectrometry (FAAS) as the detector. The experimental parameters for the MSPE procedure, such as the pH, desorption conditions, ultrasonic time and co-existing ions effects, were investigated. The adsorption capacity of the new sorbent was 14.7 mg g(-1) for Cu(2+). The detection limit of the developed method was 0.23 ng mL(-1) for Cu(2+) with an enrichment factor of 95.7. The analytical data obtained from the certified reference water and rice samples were in good agreement with the certified values. This method was also successfully applied to the determination of trace Cu(2+) in different food samples with satisfactory results. PMID:25159398</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatCC...5..849C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatCC...5..849C"><span id="translatedtitle">ENSO and greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Wenju; Santoso, Agus; Wang, Guojian; Yeh, Sang-Wook; An, Soon-Il; Cobb, Kim M.; Collins, Mat; Guilyardi, Eric; Jin, Fei-Fei; Kug, Jong-Seong; Lengaigne, Matthieu; McPhaden, Michael J.; Takahashi, Ken; Timmermann, Axel; Vecchi, Gabriel; Watanabe, Masahiro; Wu, Lixin</p> <p>2015-09-01</p> <p>The El Nio/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse <span class="hlt">warming</span> has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO and in the mean state of the Pacific climate. The projected slow-down in Walker circulation is expected to weaken equatorial Pacific Ocean currents, boosting the occurrences of eastward-propagating <span class="hlt">warm</span> surface anomalies that characterize observed extreme El Nio events. Accelerated equatorial Pacific <span class="hlt">warming</span>, particularly in the east, is expected to induce extreme rainfall in the eastern equatorial Pacific and extreme equatorward swings of the Pacific convergence zones, both of which are features of extreme El Nio. The frequency of extreme La Nia is also expected to increase in response to more extreme El Nios, an accelerated maritime continent <span class="hlt">warming</span> and surface-intensified ocean <span class="hlt">warming</span>. ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions. But model biases and recent observed strengthening of the Walker circulation highlight the need for further testing as new models, observations and insights become available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1045008','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1045008"><span id="translatedtitle"><span class="hlt">Magnetically</span> polarized Ir dopant <span class="hlt">atoms</span> in superconducting Ba(Fe1−xIrx)2As2</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dean, M.P.M.; Kim, M.G.; Kreyssig, A.; Kim, J.W.; Liu, X.; Ryan, P.J.; Thaler, A.; Budko, S.L.; Strassheim, W.; Canfield, P.C.; Hill, J.P.; Goldman, A.I.</p> <p>2012-04-25</p> <p>We investigate the <span class="hlt">magnetic</span> polarization of the Ir 5d dopant states in the pnictide superconductor Ba(Fe1−xIrx)2As2 with x=0.027(2) using Ir L3 edge x-ray resonant <span class="hlt">magnetic</span> scattering (XRMS). Despite the fact that doping partially suppresses the antiferromagnetic transition, we find that <span class="hlt">magnetic</span> order survives around the Ir dopant sites. The Ir states are <span class="hlt">magnetically</span> polarized with commensurate stripe-like antiferromagnetic order and long correlations lengths, ξmag>2800 and >850 Å, in the ab plane and along the c axis, respectively, driven by their interaction with the Fe spins. This Ir <span class="hlt">magnetic</span> order persists up to the Néel transition of the majority Fe spins at TN=74(2) K. At 5 K we find that <span class="hlt">magnetic</span> order coexists microscopically with superconductivity in Ba(Fe1−xIrx)2As2. The energy dependence of the XRMS through the Ir L3 edge shows a non-Lorentzian line shape, which we explain in terms of interference between Ir resonant scattering and Fe nonresonant <span class="hlt">magnetic</span> scattering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1069121','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1069121"><span id="translatedtitle"><span class="hlt">Atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Schwindt, Peter; Johnson, Cort N.</p> <p>2012-07-03</p> <p>An <span class="hlt">atomic</span> magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to <span class="hlt">magnetically</span> polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the <span class="hlt">magnetic</span> field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the <span class="hlt">magnetic</span> field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20982116','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20982116"><span id="translatedtitle">Ultracold <span class="hlt">atom</span>-molecule collisions and bound states in <span class="hlt">magnetic</span> fields: Tuning zero-energy Feshbach resonances in He-NH ({sup 3}{sigma}{sup -})</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gonzalez-Martinez, Maykel Leonardo; Hutson, Jeremy M.</p> <p>2007-02-15</p> <p>We have generalized the BOUND and MOLSCAT packages to allow calculations in basis sets where the monomer Hamiltonians are off diagonal and used this capability to carry out bound-state and scattering calculations on {sup 3}He-NH and {sup 4}He-NH as a function of <span class="hlt">magnetic</span> field. Following the bound-state energies to the point where they cross thresholds gives very precise predictions of the <span class="hlt">magnetic</span> fields at which zero-energy Feshbach resonances occur. We have used this to locate and characterize two very narrow Feshbach resonances in {sup 3}He-NH. Such resonances can be used to tune elastic and inelastic collision cross sections, and sweeping the <span class="hlt">magnetic</span> field across them will allow a form of quantum control in which separated <span class="hlt">atoms</span> and molecules are associated to form complexes. For the first resonance, where only elastic scattering is possible, the scattering length shows a pole as a function of <span class="hlt">magnetic</span> field and there is a very large peak in the elastic cross section. For the second resonance, however, inelastic scattering is also possible. In this case the pole in the scattering length is dramatically suppressed and the cross sections show relatively small peaks. The peak suppression is expected to be even larger in systems with stronger inelasticity. The results suggest that calculations on ultracold molecular inelastic collisions may be much less sensitive to details of the potential energy surface than has been believed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SRL.....6..115K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SRL.....6..115K"><span id="translatedtitle">Investigation of Surface <span class="hlt">Magnetic</span> Structure in Steels of a System Fe-Mn-Al-C by <span class="hlt">Atomic</span> Force Microscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klimchitskaya, G. L.; Prioli, R.; Zanette, S. I.; Caride, A. O.; Acselrad, O.; Kalashnikov, I. S.; Silva, E. M.; Simão, R. A.</p> <p></p> <p><span class="hlt">Magnetic</span> force microscopy (MFM) is used to investigate the surface <span class="hlt">magnetic</span> structure of steels Fe-28Mn-8.5Al-1C-1.4Si under the different regimes of isothermal aging. A theoretical model for the MFM imaging of such structures is developed. Calculation of van der Waals forces is performed in order to interpret the topography images. The lateral resolution in terms of the <span class="hlt">magnetic</span> field dependence on the surface coordinates is investigated. Finally, conditions that should be fulfilled for a good imaging of the samples are formulated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988EOSTr..69..820W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988EOSTr..69..820W"><span id="translatedtitle">Model predicts global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wainger, Lisa A.</p> <p></p> <p>Global greenhouse <span class="hlt">warming</span> will be clearly identifiable by the 1990s, according to eight scientists who have been studying climate changes using computer models. Researchers at NASA's Goddard Space Flight Center, Goddard Institute for Space Studies, New York, and the Massachusetts Institute of Technology, Cambridge, say that by the 2010s, most of the globe will be experiencing “substantial” <span class="hlt">warming</span>. The level of <span class="hlt">warming</span> will depend on amounts of trace gases, or greenhouse gases, in the atmosphere.Predictions for the next 70 years are based on computer simulations of Earth's climate. In three runs of the model, James Hansen and his colleagues looked at the effects of changing amounts of atmospheric gases with time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23003164','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23003164"><span id="translatedtitle">Effective control of the charge and <span class="hlt">magnetic</span> states of transition-metal <span class="hlt">atoms</span> on single-layer boron nitride.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Bing; Xiang, Hongjun; Yu, Jaejun; Wei, Su-Huai</p> <p>2012-05-18</p> <p>Developing approaches to effectively control the charge and <span class="hlt">magnetic</span> states is critical to the use of <span class="hlt">magnetic</span> nanostructures in quantum information devices but is still challenging. Here we suggest that the <span class="hlt">magnetic</span> and charge states of transition-metal (TM) doped single-layer boron-nitride (SLBN) systems can be easily controlled by the (internal) defect engineering and (external) electric fields (Eext). The relative positions and symmetries of the in-gap levels induced by defect engineering and the TM d-orbital energy levels effectively determine the charge states and <span class="hlt">magnetic</span> properties of the TM/SLBN system. Remarkably, the application of an Eext can easily control the size of the crystal field splitting of the TM d orbitals and thus, leading to the spin crossover in TM/SLBN, which could be used as Eext-driven nonvolatile memory devices. Our conclusion obtained from TM/SLBN is valid generally in other TM adsorbed layered semiconductors. PMID:23003164</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..401.1123J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..401.1123J"><span id="translatedtitle">Three-dimensional <span class="hlt">atom</span> probe analysis and <span class="hlt">magnetic</span> properties of Fe85Cu1Si2B8P4 melt spun ribbons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jafari, S.; Beitollahi, A.; Eftekhari Yekta, B.; Ohkubo, T.; Budinsky, Viktoria; Marsilius, Mie; Mollazadeh, S.; Herzer, Giselher; Hono, K.</p> <p>2016-03-01</p> <p>The effect of phosphorous on the microstructure and <span class="hlt">magnetic</span> properties of as-spun and flash annealed (389-535 °C for 7 s) Fe85Cu1Si2B8P4 melt spun ribbons were investigated by three-dimensional <span class="hlt">atom</span> probe (3DAP) and high resolution transmission electron microscopy (HRTEM) techniques. The formation of quasi-amorphous α -Fe clusters of 3-5 nm size in an amorphous matrix were detected by HRTEM, despite the high quenching rate applied by high wheel speed used. Flash annealing of the as-spun ribbons gave rise to the formation of nanocrystalline α-Fe (Si) phase in amorphous matrix containing Fe, Si, B and P elements as detected by 3DAP. Comparing 3DAP analysis of the samples annealed at 445 °C and 535 °C revealed that the concentration of P and B in amorphous matrix were increased for the latter. Further, it was shown that P hardly solidified into nanocrystalline phase and partitioned in amorphous phase alongside B <span class="hlt">atoms</span> leading to the further stabilization of amorphous matrix as confirmed by 3DAP analysis. The highest magnitude of saturation <span class="hlt">magnetic</span> induction (Bs~1.85 T) and the lowest coercive field (~10-20 A/m) were obtained for the samples annealed above 445 °C, for which noticeable reduction of saturation magnetostriction (λ s) were also detected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/accomplishments/documents/fullText/ACC0284.pdf','DOE-RDACC'); return false;" href="http://www.osti.gov/accomplishments/documents/fullText/ACC0284.pdf"><span id="translatedtitle">Observation of the Forbidden <span class="hlt">Magnetic</span> Dipole Transition 6{sup 2}P{sub ½} --> 7{sup 2}P{sub ½} in <span class="hlt">Atomic</span> Thallium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/accomplishments/fieldedsearch.html">DOE R&D Accomplishments Database</a></p> <p>Chu, S.</p> <p>1976-10-01</p> <p>A measurement of the 6{sup 2}P{sub ½} --> 7{sup 2}P{sub ½} forbidden <span class="hlt">magnetic</span> dipole matrix element in <span class="hlt">atomic</span> thallium is described. A pulsed, linearly polarized dye laser tuned to the transition frequency is used to excite the thallium vapor from the 6{sup 2}P{sub ½} ground state to the 7{sup 2}P{sub ½} excited state. Interference between the <span class="hlt">magnetic</span> dipole M1 amplitude and a static electric field induced E1 amplitude results in an <span class="hlt">atomic</span> polarization of the 7{sup 2}P{sub ½} state, and the subsequent circular polarization of 535 nm fluorescence. The circular polarization is seen to be proportional to / as expected, and measured for several transitions between hyperfine levels of the 6{sup 2}P{sub ½} and 7{sup 2}P{sub ½} states. The result is = -(2.11 +- 0.30) x 10{sup -5} parallel bar e parallel bar dirac constant/2mc, in agreement with theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26406827','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26406827"><span id="translatedtitle">Coherent coupling of alkali <span class="hlt">atoms</span> by random collisions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katz, Or; Peleg, Or; Firstenberg, Ofer</p> <p>2015-09-11</p> <p>Random spin-exchange collisions in <span class="hlt">warm</span> alkali vapor cause rapid decoherence and act to equilibrate the spin state of the <span class="hlt">atoms</span> in the vapor. In contrast, here we demonstrate experimentally and theoretically a coherent coupling of one alkali species to another species, mediated by these random collisions. We show that the minor species (potassium) inherits the <span class="hlt">magnetic</span> properties of the dominant species (rubidium), including its lifetime (T_{1}), coherence time (T_{2}), gyromagnetic ratio, and spin-exchange relaxation-free <span class="hlt">magnetic</span>-field threshold. We further show that this coupling can be completely controlled by varying the strength of the <span class="hlt">magnetic</span> field. Finally, we explain these phenomena analytically by mode mixing of the two species via spin-exchange collisions. PMID:26406827</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115k3003K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115k3003K"><span id="translatedtitle">Coherent Coupling of Alkali <span class="hlt">Atoms</span> by Random Collisions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Katz, Or; Peleg, Or; Firstenberg, Ofer</p> <p>2015-09-01</p> <p>Random spin-exchange collisions in <span class="hlt">warm</span> alkali vapor cause rapid decoherence and act to equilibrate the spin state of the <span class="hlt">atoms</span> in the vapor. In contrast, here we demonstrate experimentally and theoretically a coherent coupling of one alkali species to another species, mediated by these random collisions. We show that the minor species (potassium) inherits the <span class="hlt">magnetic</span> properties of the dominant species (rubidium), including its lifetime (T1), coherence time (T2 ), gyromagnetic ratio, and spin-exchange relaxation-free <span class="hlt">magnetic</span>-field threshold. We further show that this coupling can be completely controlled by varying the strength of the <span class="hlt">magnetic</span> field. Finally, we explain these phenomena analytically by mode mixing of the two species via spin-exchange collisions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://gallery.usgs.gov/photos/05_13_2014_vBRd7HG665_05_13_2014_1','SCIGOVIMAGE-USGS'); return false;" href="http://gallery.usgs.gov/photos/05_13_2014_vBRd7HG665_05_13_2014_1"><span id="translatedtitle"><span class="hlt">Warm</span> Springs Creek, Idaho</span></a></p> <p><a target="_blank" href=""></a></p> <p></p> <p></p> <p><span class="hlt">Warm</span> Springs Creek is a tributary of the Big Wood River in south-central Idaho. It is one of eight sites at which the USGS is conducting an ecological assessment during the summer of 2014. Study results will be published in 2015....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=architecture+AND+design&pg=5&id=EJ1002704','ERIC'); return false;" href="http://eric.ed.gov/?q=architecture+AND+design&pg=5&id=EJ1002704"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Cityscapes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jubelirer, Shelly</p> <p>2012-01-01</p> <p>Painting cityscapes is a great way to teach first-grade students about <span class="hlt">warm</span> and cool colors. Before the painting begins, the author and her class have an in-depth discussion about big cities and what types of buildings or structures that might be seen in them. They talk about large apartment and condo buildings, skyscrapers, art museums,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=talk+AND+women&pg=6&id=EJ1002704','ERIC'); return false;" href="http://eric.ed.gov/?q=talk+AND+women&pg=6&id=EJ1002704"><span id="translatedtitle"><span class="hlt">Warm</span> and Cool Cityscapes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jubelirer, Shelly</p> <p>2012-01-01</p> <p>Painting cityscapes is a great way to teach first-grade students about <span class="hlt">warm</span> and cool colors. Before the painting begins, the author and her class have an in-depth discussion about big cities and what types of buildings or structures that might be seen in them. They talk about large apartment and condo buildings, skyscrapers, art museums,</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED263758.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED263758.pdf"><span id="translatedtitle"><span class="hlt">Warming</span> Up to Communication.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Garner, Lucia Caycedo; Rusch, Debbie</p> <p></p> <p>Daily <span class="hlt">warm</span>-up exercises are advocated as a means of bridging the gap between previously unrelated activities outside the classroom and immersion into the second language, relaxing the class, and establishing a mood for communication. Variety, careful preparation, assuring that the students understand the activity, feeling free to discontinue an…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApSS..358..619M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApSS..358..619M"><span id="translatedtitle">Tailoring the electric and <span class="hlt">magnetic</span> properties of submicron-sized metallic multilayered systems by TVA <span class="hlt">atomic</span> inter-diffusion engineered processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miculescu, F.; Jepu, I.; Stan, G. E.; Miculescu, M.; Voicu, S. I.; Cotrut, C.; Pisu, T. Machedon; Ciuca, S.</p> <p>2015-12-01</p> <p>Thermo-ionic Vacuum Arc evaporation method was selected for the synthesis of Fe/Cu/Ni/Cu multilayer structures on Si (1 0 0) substrates. The aim of the study was the preparation and characterization of structures featuring a giant magnetoresistance effect. This was accomplished by inducing the formation of nanosized ferromagnetic crystallites in multilayer nonmagnetic solutions via <span class="hlt">atomic</span> inter-diffusion processes by the tuning of deposition parameters. Layer-by-layer and inter-diffused type structures were prepared and comparatively analyzed by scanning electron microscopy, X-ray microanalysis, <span class="hlt">atomic</span> force microscopy, X-ray diffraction and high-resolution transmission electron microscopy coupled with selected area electron diffraction. We presented the influence of the microstructure on electric and <span class="hlt">magnetic</span> properties of the submicron-sized multilayers. The dependence of the electric resistance and the magnetoresistance on the composition, structure, morphology and roughness of the layers was established. We obtained an electric resistance value of 1.22 Ω for the layer-by-layer type structure, and 0.46 Ω for the inter-diffusion designed structure. Using the <span class="hlt">atomic</span> inter-diffusion we succeeded in achieving an improvement of the magnetoresistive effect, from 0.1% to 2.3%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340370','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340370"><span id="translatedtitle">Influence of ball milling on <span class="hlt">atomic</span> structure and <span class="hlt">magnetic</span> properties of Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} glassy alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Taghvaei, Amir Hossein; Stoica, Mihai; Bednarčik, Jozef; Kaban, Ivan; Shahabi, Hamed Shakur; Khoshkhoo, Mohsen Samadi; Janghorban, Kamal; Eckert, Jürgen</p> <p>2014-06-01</p> <p>The influence of ball milling on the <span class="hlt">atomic</span> structure and <span class="hlt">magnetic</span> properties of the Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} metallic glass with a high thermal stability and excellent soft <span class="hlt">magnetic</span> properties has been investigated. After 14 h of milling, the obtained powders were found to consist mainly of an amorphous phase and a small fraction of the (Co,Fe){sub 21}Ta{sub 2}B{sub 6} nanocrystals. The changes in the reduced pair correlation functions suggest noticeable changes in the <span class="hlt">atomic</span> structure of the amorphous upon ball milling. Furthermore, it has been shown that milling is accompanied by introduction of compressive and dilatational sites in the glassy phase and increasing the fluctuation of the <span class="hlt">atomic</span>-level hydrostatic stress without affecting the coordination number of the nearest neighbors. Ball milling has decreased the thermal stability and significantly affected the <span class="hlt">magnetic</span> properties through increasing the saturation <span class="hlt">magnetization</span>, Curie temperature of the amorphous phase and coercivity. - Highlights: • Ball milling affected the <span class="hlt">atomic</span> structure of Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} metallic glass. • Mechanically-induced crystallization started after 4 h milling. • Milling increased the fluctuation of the <span class="hlt">atomic</span>-level hydrostatic stress in glass. • Ball milling influenced the thermal stability and <span class="hlt">magnetic</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023746','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023746"><span id="translatedtitle">Identifying the Molecular Origin of Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.</p> <p>2009-01-01</p> <p>We have investigated the physical characteristics of greenhouse gases (GHGs) to assess which properties are most important in determining the efficiency of a GHG. Chlorofluorcarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), nitrogen fluorides, and various other known atmospheric trace molecules have been included in this study. Compounds containing the halogens F or Cl have in common very polar X-F or X-Cl bonds, particularly the X-F bonds. It is shown that as more F <span class="hlt">atoms</span> bond to the same central <span class="hlt">atom</span>, the bond dipoles become larger as a result of the central <span class="hlt">atom</span> becoming more positive. This leads to a linear increase in the total or integrated XF bond dipole derivatives for the molecule, which leads to a non-linear (quadratic) increase in infrared (IR) intensity. Moreover, virtually all of the X-F bond stretches occur in the atmospheric IR window as opposed to X-H stretches, which do not occur in the atmospheric window. It is concluded that molecules possessing several F <span class="hlt">atoms</span> will always have a large radiative forcing parameter in the calculation of their global <span class="hlt">warming</span> potential. Some of the implications for global <span class="hlt">warming</span> and climate change are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1088635','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1088635"><span id="translatedtitle">Electronic Structures and <span class="hlt">Magnetic</span> Properties of MoS2 Nanostructures: <span class="hlt">Atomic</span> Defects, Nanoholes, Nanodots and Antidots</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou, Yungang; Yang, Ping; Zu, Haoyue; Gao, Fei; Zu, Xiaotao</p> <p>2013-04-24</p> <p>MoS2-based nanostructures, including <span class="hlt">atomic</span> defect, nanohole, nanodot and antidot, are characterized with spin-polarized density functional theory. The S-vacancy defect is more likely to form than the Mo-vacancy defect due to the formation of Mo-Mo metallic bonds. Among different shaped nanoholes and nanodots, triangle ones associated with ferromagnetic characteristic are the most energetically favorable, and exhibit unexpected large spin moment that is scaled linearly with edged length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1046906','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1046906"><span id="translatedtitle">Effective Control of the Charge and <span class="hlt">Magnetic</span> States of Transition-Metal <span class="hlt">Atoms</span> on Single-Layer Boron Nitride</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, B.; Xiang, H. J.; Yu, J. J.; Wei, S. H.</p> <p>2012-05-18</p> <p>Developing approaches to effectively control the charge and <span class="hlt">magnetic</span> states is critical to the use of <span class="hlt">magnetic</span> nanostructures in quantum information devices but is still challenging. Here we suggest that the <span class="hlt">magnetic</span> and charge states of transition-metal (TM) doped single-layer boron-nitride (SLBN) systems can be easily controlled by the (internal) defect engineering and (external) electric fields (E{sub ext}). The relative positions and symmetries of the in-gap levels induced by defect engineering and the TM d-orbital energy levels effectively determine the charge states and <span class="hlt">magnetic</span> properties of the TM/SLBN system. Remarkably, the application of an E{sub ext} can easily control the size of the crystal field splitting of the TM d orbitals and thus, leading to the spin crossover in TM/SLBN, which could be used as E{sub ext}-driven nonvolatile memory devices. Our conclusion obtained from TM/SLBN is valid generally in other TM adsorbed layered semiconductors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatGe...8...87B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatGe...8...87B"><span id="translatedtitle">Climate science: Pacemakers of <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brnnimann, Stefan</p> <p>2015-02-01</p> <p>In the first decades of the twentieth century, the Earth <span class="hlt">warmed</span> rapidly. A coral-based climate proxy record of westerly winds over the equatorial Pacific suggests that wind strength and <span class="hlt">warming</span> rate were linked, as they are today.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21550102','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21550102"><span id="translatedtitle">Laser spectroscopy of the 4s4p {sup 3}P{sub 2} - 4s3d {sup 1}D{sub 2} transition on <span class="hlt">magnetically</span> trapped calcium <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dammalapati, U.; Norris, I.; Burrows, C.; Riis, E.</p> <p>2011-06-15</p> <p>Laser excitation of the 4s4p {sup 3}P{sub 2} - 4s3d {sup 1}D{sub 2} transition in <span class="hlt">atomic</span> calcium has been observed and the wavelength determined to 1530.5298(6) nm. The metastable 4s4p {sup 3}P{sub 2} <span class="hlt">atoms</span> were <span class="hlt">magnetically</span> trapped in the quadrupole <span class="hlt">magnetic</span> field of a magneto-optical trap. This state represents the only ''loss'' channel for the calcium <span class="hlt">atoms</span> when laser cooled on the 4s{sup 2} {sup 1}S{sub 0} - 4s4p {sup 1}P{sub 1} transition. A rate equation model shows that an order of magnitude more <span class="hlt">atoms</span> are trapped in this state compared with those taking part in the main cooling cycle. Excitation of the {sup 3}P{sub 2} <span class="hlt">atoms</span> back up to the 4s3d {sup 1}D{sub 2} state provides a means of accessing these <span class="hlt">atoms</span>. Efficient repumping is achieved if the 1530-nm laser is used in conjunction with a 672-nm laser driving the 4s3d {sup 1}D{sub 2} - 4s5p {sup 1}P{sub 1} transition. In the present experiment, we detected about 4.5x10{sup 4} trapped {sup 3}P{sub 2} <span class="hlt">atoms</span>, a relatively low <span class="hlt">atom</span> density, and measured a lifetime of approximately 1 s, which is limited by background collisions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NatPh...7..520S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NatPh...7..520S"><span id="translatedtitle">Anti-<span class="hlt">atoms</span>: Gotcha!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Surko, Clifford M.</p> <p>2011-07-01</p> <p>Refined techniques to mix cold antiprotons and positrons in a <span class="hlt">magnetic</span> bottle show that antihydrogen <span class="hlt">atoms</span> can be trapped for 15 minutes -- an improvement of four orders of magnitude over previous experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=209721','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=209721"><span id="translatedtitle">PERENNIAL <span class="hlt">WARM</span>-SEASON GRASSES</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p><span class="hlt">Warm</span>-season grasses and can be used to augment the forage supply for grazing livestock operations in the northeastern U.S. Much of what is known about <span class="hlt">warm</span> season grass production and management in the northeastern US was obtained from a soil conservation or wildlife habitat perspective. <span class="hlt">Warm</span>-seas...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/850076','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/850076"><span id="translatedtitle">Microstructual investigation of mixed rar earth iron boron processed vis melt-spinning and high-pressure gas-<span class="hlt">atomization</span> for isotrophic bonded permanent <span class="hlt">magnets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Buelow, Nicholas Lee</p> <p>2005-08-01</p> <p>A solid solution of three rare earths (RE) in the RE{sub 2}Fe{sub 14}B structure have been combined to create the novel mixed rare earth iron boron (MRE{sub 2}Fe{sub 14}B) alloy family. MRE{sub 2}Fe{sub 14}B exhibits reduced temperature dependent <span class="hlt">magnetic</span> properties; remanence and coercivity. The desired form of MRE{sub 2}Fe{sub 14}B is a powder that can be blended with a polymer binder and compression or injection molded to form an isotropic polymer bonded permanent <span class="hlt">magnet</span> (PBM). Commercially, Nd{sub 2}Fe{sub 14}B is the alloy of choice for PBMs. Powders of Nd{sub 2}Fe{sub 14}B are made via melt-spinning as can be MRE{sub 2}Fe{sub 14}B which allows for direct comparisons. MRE{sub 2}Fe{sub 14}B made using melt-spinning at high wheel speeds is overquenched and must be annealed to an optimal hard <span class="hlt">magnetic</span> state. Due to the rare earth content in the MRE{sub 2}Fe{sub 14}B powders, they must be protected from the environment in which they operate. This protection is accomplished by using a modified fluidized bed process to grow a protective fluoride coating nominally 15nm thick, to reduce air oxidation. MRE{sub 2}Fe{sub 14}B has demonstrated reduced temperature dependent <span class="hlt">magnetic</span> properties in ribbon and PBM form. The real challenge has been modifying alloy designs that were successfully melt-spun to be compatible with high-pressure gas-<span class="hlt">atomization</span> (HPGA). The cooling rates in HPGA are lower than melt-spinning, as the powders are quenched via convective cooling, compared to melt-spinning, which quenches initially by conductive cooling. Early alloy designs, in gas <span class="hlt">atomized</span> and melt-spun form, did not have similar phase compositions or microstructures. Alloy additions, such as the addition of zirconium as a nucleation catalyst, were successful in creating similar phases and microstructures in the HPGA powders and melt-spun ribbon of the same MRE{sub 2}Fe{sub 14}B composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JChPh.131i5101N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JChPh.131i5101N"><span id="translatedtitle"><span class="hlt">Atomic</span> resolution protein structure determination by three-dimensional transferred echo double resonance solid-state nuclear <span class="hlt">magnetic</span> resonance spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nieuwkoop, Andrew J.; Wylie, Benjamin J.; Franks, W. Trent; Shah, Gautam J.; Rienstra, Chad M.</p> <p>2009-09-01</p> <p>We show that quantitative internuclear N15-C13 distances can be obtained in sufficient quantity to determine a complete, high-resolution structure of a moderately sized protein by magic-angle spinning solid-state NMR spectroscopy. The three-dimensional ZF-TEDOR pulse sequence is employed in combination with sparse labeling of C13 sites in the ?1 domain of the immunoglobulin binding protein G (GB1), as obtained by bacterial expression with 1,3-C13 or 2-C13-glycerol as the C13 source. Quantitative dipolar trajectories are extracted from two-dimensional N15-C13 planes, in which 750 cross peaks are resolved. The experimental data are fit to exact theoretical trajectories for spin clusters (consisting of one C13 and several N15 each), yielding quantitative precision as good as 0.1 for 350 sites, better than 0.3 for another 150, and 1.0 for 150 distances in the range of 5-8 . Along with isotropic chemical shift-based (TALOS) dihedral angle restraints, the distance restraints are incorporated into simulated annealing calculations to yield a highly precise structure (backbone RMSD of 0.250.09 ), which also demonstrates excellent agreement with the most closely related crystal structure of GB1 (2QMT, bbRMSD 0.790.03 ). Moreover, side chain heavy <span class="hlt">atoms</span> are well restrained (0.760.06 total heavy <span class="hlt">atom</span> RMSD). These results demonstrate for the first time that quantitative internuclear distances can be measured throughout an entire solid protein to yield an <span class="hlt">atomic</span>-resolution structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2832044','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2832044"><span id="translatedtitle"><span class="hlt">Atomic</span> resolution protein structure determination by three-dimensional transferred echo double resonance solid-state nuclear <span class="hlt">magnetic</span> resonance spectroscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nieuwkoop, Andrew J.; Wylie, Benjamin J.; Franks, W. Trent; Shah, Gautam J.; Rienstra, Chad M.</p> <p>2009-01-01</p> <p>We show that quantitative internuclear 15N–13C distances can be obtained in sufficient quantity to determine a complete, high-resolution structure of a moderately sized protein by magic-angle spinning solid-state NMR spectroscopy. The three-dimensional ZF-TEDOR pulse sequence is employed in combination with sparse labeling of 13C sites in the β1 domain of the immunoglobulin binding protein G (GB1), as obtained by bacterial expression with 1,3-13C or 2-13C-glycerol as the 13C source. Quantitative dipolar trajectories are extracted from two-dimensional 15N–13C planes, in which ∼750 cross peaks are resolved. The experimental data are fit to exact theoretical trajectories for spin clusters (consisting of one 13C and several 15N each), yielding quantitative precision as good as 0.1 Å for ∼350 sites, better than 0.3 Å for another 150, and ∼1.0 Å for 150 distances in the range of 5–8 Å. Along with isotropic chemical shift-based (TALOS) dihedral angle restraints, the distance restraints are incorporated into simulated annealing calculations to yield a highly precise structure (backbone RMSD of 0.25±0.09 Å), which also demonstrates excellent agreement with the most closely related crystal structure of GB1 (2QMT, bbRMSD 0.79±0.03 Å). Moreover, side chain heavy <span class="hlt">atoms</span> are well restrained (0.76±0.06 Å total heavy <span class="hlt">atom</span> RMSD). These results demonstrate for the first time that quantitative internuclear distances can be measured throughout an entire solid protein to yield an <span class="hlt">atomic</span>-resolution structure. PMID:19739873</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93n0101P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93n0101P"><span id="translatedtitle">Electronic and <span class="hlt">magnetic</span> properties of single Fe <span class="hlt">atoms</span> on a CuN surface: Effects of electron correlations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panda, S. K.; Di Marco, I.; Grânäs, O.; Eriksson, O.; Fransson, J.</p> <p>2016-04-01</p> <p>The electronic structure and <span class="hlt">magnetic</span> properties of a single Fe adatom on a CuN surface have been studied using density functional theory in the local spin density approximation (LSDA), the LSDA+U approach, and the local density approximation plus dynamical mean-field theory (LDA+DMFT). The impurity problem in LDA+DMFT is solved through exact diagonalization and in the Hubbard-I approximation. The comparison of the one-particle spectral functions obtained from LSDA, LSDA+U, and LDA+DMFT show the importance of dynamical correlations for the electronic structure of this system. Most importantly, we focused on the <span class="hlt">magnetic</span> anisotropy and found that neither LSDA nor LSDA+U can explain the measured high values of the axial and transverse anisotropy parameters. Instead, the spin excitation energies obtained from our LDA+DMFT approach with exact diagonalization agree significantly better with experimental data. This affirms the importance of treating fluctuating <span class="hlt">magnetic</span> moments through a realistic many-body treatment when describing this class of nanomagnetic systems. Moreover, it facilitates insight to the role of the hybridization with surrounding orbitals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AmJPh..83..513M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AmJPh..83..513M"><span id="translatedtitle">Analysis of off-axis solenoid fields using the <span class="hlt">magnetic</span> scalar potential: An application to a Zeeman-slower for cold <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muniz, Srgio R.; Bagnato, Vanderlei S.; Bhattacharya, M.</p> <p>2015-06-01</p> <p>In a region free of currents, magnetostatics can be described by the Laplace equation of a scalar <span class="hlt">magnetic</span> potential, and one can apply the same methods commonly used in electrostatics. Here, we show how to calculate the general vector field inside a real (finite) solenoid, using only the magnitude of the field along the symmetry axis. Our method does not require integration or knowledge of the current distribution and is presented through practical examples, including a nonuniform finite solenoid used to produce cold <span class="hlt">atomic</span> beams via laser cooling. These examples allow educators to discuss the nontrivial calculation of fields off-axis using concepts familiar to most students, while offering the opportunity to introduce themes of current modern research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23273544','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23273544"><span id="translatedtitle">Surface-initiated <span class="hlt">atom</span> transfer radical polymerization of polyamine grafting from <span class="hlt">magnetic</span> iron oxide submicroparticles for high adsorption capacity of cadmium in aqueous solution.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Qingyang; Ji, Zhongxing; Bei, Yiling</p> <p>2013-03-15</p> <p>Chemical modification of <span class="hlt">magnetic</span> submicroparticles (MSPs) with functional polymers using controlled/living radical polymerization method has recently gained a great deal of attentions because of the potential applications to water treatment. In this work, we demonstrated an efficient method for poly(glycidyl methacrylate) (pGMA) modification of MSPs, by surface-initiated <span class="hlt">atom</span> transfer radical polymerization method, and then, the particles were actually modified by triethylenetetramine through epoxy groups of pGMA to form polyamine/MSPs. The material was characterized using infrared spectroscopy, thermo gravimetric analyzer, transmission electron microscopic, gel permeation chromatography, and vibrating sample magnetometer. Sorption of Cd(II) to polyamine/MSPs reached equilibrium in ~100 min and agreed well to the Freundlich isotherm equation with maximum adsorption capacity of 71.3 mg g(-1) for the 500 mg L(-1) Cd(II) aqueous solution at neutral pH. PMID:23273544</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3397B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3397B"><span id="translatedtitle">Global <span class="hlt">Warming</span> And Meltwater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bratu, S.</p> <p>2012-04-01</p> <p>In order to find new approaches and new ideas for my students to appreciate the importance of science in their daily life, I proposed a theme for them to debate. They had to search for global <span class="hlt">warming</span> information and illustrations in the media, and discuss the articles they found in the classroom. This task inspired them to search for new information about this important and timely theme in science. I informed my students that all the best information about global <span class="hlt">warming</span> and meltwater they found would be used in a poster that would help us to update the knowledge base of the Physics laboratory. I guided them to choose the most eloquent images and significant information. Searching and working to create this poster, the students arrived to better appreciate the importance of science in their daily life and to critically evaluate scientific information transmitted via the media. In the poster we created, one can find images, photos and diagrams and some interesting information: Global <span class="hlt">warming</span> refers to the rising average temperature of the Earth's atmosphere and oceans and its projected evolution. In the last 100 years, the Earth's average surface temperature increased by about 0.8 °C with about two thirds of the increase occurring over just the last three decades. <span class="hlt">Warming</span> of the climate system is unequivocal, and scientists are more than 90% certain most of it is caused by increasing concentrations of greenhouse gases produced by human activities such as deforestation and burning fossil fuel. They indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C for the lowest emissions scenario and 2.4 to 6.4 °C for the highest predictions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, and potentially result in expansion of subtropical deserts. <span class="hlt">Warming</span> is expected to be strongest in the Arctic and would be associated with continuing decrease of glaciers, permafrost and sea ice. Other likely effects of the <span class="hlt">warming</span> include more frequent occurrences of extreme weather events including heat waves, droughts and heavy rainfall events, species extinctions due to shifting temperature regimes, and changes in agricultural yields. Meltwater is the water released by the melting of snow or ice, including glacial ice and ice shelves in the oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reduced. In a report published in June 2007, the United Nations Environment Program estimated that global <span class="hlt">warming</span> could lead to 40% of the world's population being affected by the loss of glaciers, snow and the associated meltwater in Asia. This is one of many activities of the physics laboratory that the students of our high school are involved in.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JAP...105gA728T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JAP...105gA728T"><span id="translatedtitle"><span class="hlt">Magnetic</span> properties and microstructure of gas <span class="hlt">atomized</span> MRE2(Fe,Co)14B powder with ZrC addition (MRE=Nd+Y+Dy)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, W.; Wu, Y. Q.; Dennis, K. W.; Oster, N. T.; Kramer, M. J.; Anderson, I. E.; McCallum, R. W.</p> <p>2009-04-01</p> <p>Gas <span class="hlt">atomization</span> powder with Zr substitutions for the MRE and ZrC additions were systematically studied. The results show that the partial substitutions of Zr and the ZrC additions effectively improved glass formability in the alloys. Scanning electron microscopy (SEM) revealed that the as-<span class="hlt">atomized</span> powder with a particle size of less than 32 μm is predominately uniform equiaxed grains with an average grain size of 1.5 μm. X-ray diffraction and differential thermal analysis measurements detected very tiny amounts of amorphous phase. After annealing at 700 °C for 15 min, the SEM grain microstructure exhibits a minor change, but <span class="hlt">magnetic</span> properties are substantially improved. M versus T measurements reveal that the phase composition evolved from 2:14:1 plus a small amount of 2:17 phases to a single 2:14:1 phase during the annealing process. The sieve analysis of the powders showed a particle size distribution with 90 wt % of the powder less than 45 μm. The <span class="hlt">magnetic</span> properties of the annealed powder varied with particle size. (BH)max first increases with increasing particle size from 5 μm, reaches the peak value in the size range of 20-25 μm, and then decreases with increasing particle size. For the 20-25 μm powder sample annealed at 700 °C for 15 min, the (BH)max of 9.6 MG Oe at room temperature and 5.6 MG Oe at 200 °C were obtained, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/977179','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/977179"><span id="translatedtitle"><span class="hlt">Magnetic</span> properties and microstructure of gas <span class="hlt">atomized</span> MRE2(Fe, Co)14B powder with ZrC addition (MRE=Nd + Y + Dy)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tang, W.; Wu, Y. Q.; Dennis, K.; Oster, N.; Kramer, M.; Anderson, I.; McCallum, R.</p> <p>2009-05-12</p> <p>Gas <span class="hlt">atomization</span> powder with Zr substitutions for the MRE and ZrC additions were systematically studied. The results show that the partial substitutions of Zr and the ZrC additions effectively improved glass formability in the alloys. Scanning electron microscopy (SEM) revealed that the as-<span class="hlt">atomized</span> powder with a particle size of less than 32 {micro}m is predominately uniform equiaxed grains with an average grain size of 1.5 {micro}m. X-ray diffraction and differential thermal analysis measurements detected very tiny amounts of amorphous phase. After annealing at 700 C for 15 min, the SEM grain microstructure exhibits a minor change, but <span class="hlt">magnetic</span> properties are substantially improved. M versus T measurements reveal that the phase composition evolved from 2:14:1 plus a small amount of 2:17 phases to a single 2:14:1 phase during the annealing process. The sieve analysis of the powders showed a particle size distribution with 90 wt % of the powder less than 45 {micro}m. The <span class="hlt">magnetic</span> properties of the annealed powder varied with particle size. (BH){sub max} first increases with increasing particle size from 5 {micro}m, reaches the peak value in the size range of 20-25 {micro}m, and then decreases with increasing particle size. For the 20-25 {micro}m powder sample annealed at 700 C for 15 min, the (BH){sub max} of 9.6 MG Oe at room temperature and 5.6 MG Oe at 200 C were obtained, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyE...75..169L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyE...75..169L"><span id="translatedtitle">Spin and orbital <span class="hlt">magnetic</span> moments and spin anisotropy energies of light rare earth <span class="hlt">atoms</span> embedded in graphene: A first-principles study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Ya-Jing; Wang, Min; Tang, Meng-yu; Tian, Xing; Gao, Shan; He, Zhen; Li, Ying; Zhou, Tie-Ge</p> <p>2016-01-01</p> <p>The geometries, electronic structures, spin <span class="hlt">magnetic</span> moments (SMMs), orbital <span class="hlt">magnetic</span> moments (OMMs) and spin anisotropy energies (SAEs) of light rare earth <span class="hlt">atoms</span> (La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd) embedded in graphene were studied by using first-principles calculations based on Density Functional Theory (DFT). The spin-orbital coupling effect was taken into account and GGA+U method was adopted to describe the strongly localized and correlated 4f electrons. There is a significant deformation of the graphene plane after doping and optimization. The deformation of Gd doped graphene is the largest, while Eu the smallest. The results show that the valence is +3 for La, Ce, Pr, Nd, Pm, Sm and Gd, and +2 for Eu. Except Eu and Gd, there are obvious OMMs. When the spin is in the Z direction, the OMMs are -0.941 μB, -1.663 μB, -3.239 μB, -3.276 μB and -3.337 μB for Ce, Pr, Nd, Pm and Sm, respectively, and point the opposite direction of SMMs. All the doped systems except Gd show considerable SAEs. For Ce, Pr, Nd, Pm, Sm, and Eu, the SAEs are -0.928 meV, 20.941 meV, -8.848 meV, 7.855 meV, 75.070 meV and 0.810 meV, respectively. When the spin orientation is different, different orbital angular moments lead to apparent charge density difference of the 4f <span class="hlt">atoms</span>, which can also explain the origin of SAEs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6823689','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6823689"><span id="translatedtitle">Global <span class="hlt">warming</span> - A reduced threat</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Michaels, P.J.; Stooksbury, D.E. )</p> <p>1992-10-01</p> <p>Issues associated with global <span class="hlt">warming</span> are analyzed focusing on global and hemispheric temperature histories and trace gas concentrations; artificial <span class="hlt">warming</span> from urban heat islands; high-latitude and diurnal temperatures; recent climate models; direct effects on vegetation of an increase in carbon dioxide; and compensatory cooling from other industrial products. Data obtained indicate that anthropogenerated sulfate emissions are mitigating some of the <span class="hlt">warming</span>, and that increased cloudiness as a result of these emissions will further enhance night, rather than day, <span class="hlt">warming</span>. It is noted that the sulfate emissions are not sufficient to explain all of the night <span class="hlt">warming</span>. The sensitivity of climate to anthropogenerated aerosols, and the general lack of previously predicted <span class="hlt">warming</span>, could drastically alter the debate on global <span class="hlt">warming</span> in favor of less expensive policies. 61 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4321315','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4321315"><span id="translatedtitle">Imaging Dirac-mass disorder from <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J. L.; Zhong, Ruidan; Schneeloch, John A.; Liu, Tiansheng; Valla, Tonica; Tranquada, John M.; Gu, Genda; Davis, J. C. Séamus</p> <p>2015-01-01</p> <p>To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a “Dirac-mass gap” in their spectrum by breaking time-reversal symmetry. Use of <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> influence the Dirac-mass gap at the <span class="hlt">atomic</span> scale or, conversely, whether the ferromagnetic interactions between dopant <span class="hlt">atoms</span> are influenced by the topological surface states. Here we image the locations of the <span class="hlt">magnetic</span> (Cr) dopant <span class="hlt">atoms</span> in the ferromagnetic TI Cr0.08(Bi0.1Sb0.9)1.92Te3. Simultaneous visualization of the Dirac-mass gap Δ(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr <span class="hlt">atom</span> areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of Δ(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship Δ(r)∝n(r) is confirmed throughout and exhibits an electron–dopant interaction energy J* = 145 meV·nm2. These observations reveal how <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential. PMID:25605947</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25605947','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25605947"><span id="translatedtitle">Imaging Dirac-mass disorder from <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J L; Zhong, Ruidan; Schneeloch, John A; Liu, Tiansheng; Valla, Tonica; Tranquada, John M; Gu, Genda; Davis, J C Séamus</p> <p>2015-02-01</p> <p>To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a "Dirac-mass gap" in their spectrum by breaking time-reversal symmetry. Use of <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> influence the Dirac-mass gap at the <span class="hlt">atomic</span> scale or, conversely, whether the ferromagnetic interactions between dopant <span class="hlt">atoms</span> are influenced by the topological surface states. Here we image the locations of the <span class="hlt">magnetic</span> (Cr) dopant <span class="hlt">atoms</span> in the ferromagnetic TI Cr0.08(Bi0.1Sb0.9)1.92Te3. Simultaneous visualization of the Dirac-mass gap Δ(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr <span class="hlt">atom</span> areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of Δ(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship [Formula: see text] is confirmed throughout and exhibits an electron-dopant interaction energy J* = 145 meV·nm(2). These observations reveal how <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential. PMID:25605947</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1182501-imaging-dirac-mass-disorder-from-magnetic-dopant-atoms-ferromagnetic-topological-insulator-crx-bi0-xte3','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1182501-imaging-dirac-mass-disorder-from-magnetic-dopant-atoms-ferromagnetic-topological-insulator-crx-bi0-xte3"><span id="translatedtitle">Imaging Dirac-mass disorder from <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Lee, Inhee; Kim, Chung Koo; Lee, Jinho; Billinge, Simon J. L.; Zhong, Ruidan D.; Schneeloch, John A.; Liu, Tiansheng S.; Valla, Tonica; Tranquada, John M.; Gu, Genda D.; et al</p> <p>2015-01-20</p> <p>To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a “Dirac-mass gap” in their spectrum by breaking time-reversal symmetry. Use of <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> influence the Dirac-mass gap at the <span class="hlt">atomic</span> scale or, conversely, whether the ferromagnetic interactions between dopant <span class="hlt">atoms</span> are influenced by the topological surface states. Here we image the locations of the <span class="hlt">magnetic</span> (Cr) dopant <span class="hlt">atoms</span> in themore » ferromagnetic TI Cr₀.₀₈(Bi₀.₁Sb₀.₉)₁.₉₂Te₃. Simultaneous visualization of the Dirac-mass gap Δ(r) reveals its intense disorder, which we demonstrate is directly related to fluctuations in n(r), the Cr <span class="hlt">atom</span> areal density in the termination layer. We find the relationship of surface-state Fermi wavevectors to the anisotropic structure of Δ(r) not inconsistent with predictions for surface ferromagnetism mediated by those states. Moreover, despite the intense Dirac-mass disorder, the anticipated relationship Δ(r)∝n(r) is confirmed throughout and exhibits an electron–dopant interaction energy J* = 145 meV·nm². In addition, these observations reveal how <span class="hlt">magnetic</span> dopant <span class="hlt">atoms</span> actually generate the TI mass gap locally and that, to achieve the novel physics expected of time-reversal symmetry breaking TI materials, control of the resulting Dirac-mass gap disorder will be essential.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CoPhC.183.1502S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CoPhC.183.1502S"><span id="translatedtitle">A highly optimized code for calculating <span class="hlt">atomic</span> data at neutron star <span class="hlt">magnetic</span> field strengths using a doubly self-consistent Hartree-Fock-Roothaan method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schimeczek, C.; Engel, D.; Wunner, G.</p> <p>2012-07-01</p> <p>Our previously published code for calculating energies and bound-bound transitions of medium-Z elements at neutron star <span class="hlt">magnetic</span> field strengths [D. Engel, M. Klews, G. Wunner, Comput. Phys. Comm. 180 (2009) 302-311] was based on the adiabatic approximation. It assumes a complete decoupling of the (fast) gyration of the electrons under the action of the <span class="hlt">magnetic</span> field and the (slow) bound motion along the field under the action of the Coulomb forces. For the single-particle orbitals this implied that each is a product of a Landau state and an (unknown) longitudinal wave function whose B-spline coefficients were determined self-consistently by solving the Hartree-Fock equations for the many-electron problem on a finite-element grid. In the present code we go beyond the adiabatic approximation, by allowing the transverse part of each orbital to be a superposition of Landau states, while assuming that the longitudinal part can be approximated by the same wave function in each Landau level. Inserting this ansatz into the energy variational principle leads to a system of coupled equations in which the B-spline coefficients depend on the weights of the individual Landau states, and vice versa, and which therefore has to be solved in a doubly self-consistent manner. The extended ansatz takes into account the back-reaction of the Coulomb motion of the electrons along the field direction on their motion in the plane perpendicular to the field, an effect which cannot be captured by the adiabatic approximation. The new code allows for the inclusion of up to 8 Landau levels. This reduces the relative error of energy values as compared to the adiabatic approximation results by typically a factor of three (1/3 of the original error), and yields accurate results also in regions of lower neutron star <span class="hlt">magnetic</span> field strengths where the adiabatic approximation fails. Further improvements in the code are a more sophisticated choice of the initial wave functions, which takes into account the shielding of the core potential for outer electrons by inner electrons, and an optimal finite-element decomposition of each individual longitudinal wave function. These measures largely enhance the convergence properties compared to the previous code, and lead to speed-ups by factors up to two orders of magnitude compared with the implementation of the Hartree-Fock-Roothaan method used by Engel and Wunner in [D. Engel, G. Wunner, Phys. Rev. A 78 (2008) 032515]. New version program summaryProgram title: HFFER II Catalogue identifier: AECC_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECC_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: v 55 130 No. of bytes in distributed program, including test data, etc.: 293 700 Distribution format: tar.gz Programming language: Fortran 95 Computer: Cluster of 1-13 HP Compaq dc5750 Operating system: Linux Has the code been vectorized or parallelized?: Yes, parallelized using MPI directives. RAM: 1 GByte per node Classification: 2.1 External routines: MPI/GFortran, LAPACK, BLAS, FMlib (included in the package) Catalogue identifier of previous version: AECC_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 302 Does the new version supersede the previous version?: Yes Nature of problem: Quantitative modellings of features observed in the X-ray spectra of isolated <span class="hlt">magnetic</span> neutron stars are hampered by the lack of sufficiently large and accurate databases for <span class="hlt">atoms</span> and ions up to the last fusion product, iron, at strong <span class="hlt">magnetic</span> field strengths. Our code is intended to provide a powerful tool for calculating energies and oscillator strengths of medium-Z <span class="hlt">atoms</span> and ions at neutron star <span class="hlt">magnetic</span> field strengths with sufficient accuracy in a routine way to create such databases. Solution method: The Slater determinants of the <span class="hlt">atomic</span> wave functions are constructed from single-particle orbitals ψi which are products of a wave function in the z direction (the direction of the <span class="hlt">magnetic</span> field) and an expansion of the wave function perpendicular to the direction of the <span class="hlt">magnetic</span> field in terms of Landau states, ψi(ρ,φ,z)=Pi(z)∑n=0NLtinϕni(ρ,φ). The tin are expansion coefficients, and the expansion is cut off at some maximum Landau level quantum number n=NL. In the previous version of the code only the lowest Landau level was included (NL=0), in the new version NL can take values of up to 7. As in the previous version of the code, the longitudinal wave functions are expanded in terms of sixth-order B-splines on finite elements on the z axis, with a combination of equidistant and quadratically widening element borders. Both the B-spline expansion coefficients and the Landau weights tin of all orbitals have to be determined in a doubly self-consistent way: For a given set of Landau weights tin, the system of linear equations for the B-spline expansion coefficients, which is equivalent to the Hartree-Fock equations for the longitudinal wave functions, is solved numerically. In the second step, for frozen B-spline coefficients new Landau weights are determined by minimizing the total energy with respect to the Landau expansion coefficients. Both steps require solving non-linear eigenvalue problems of Roothaan type. The procedure is repeated until convergence of both the B-spline coefficients and the Landau weights is achieved. Reasons for new version: The former version of the code was restricted to the adiabatic approximation, which assumes the quantum dynamics of the electrons in the plane perpendicular to the <span class="hlt">magnetic</span> field to be fixed in the lowest Landau level, n=0. This approximation is valid only if the <span class="hlt">magnetic</span> field strengths are large compared to the reference <span class="hlt">magnetic</span> field BZ, for a nuclear charge Z,BZ=Z24.70108×105 T. Summary of revisions: In the new version, the transverse parts of the orbitals are expanded in terms of Landau states up to n=7, and the expansion coefficients are determined, together with the longitudinal wave functions, in a doubly self-consistent way. Thus the back-reaction of the quantum dynamics along the <span class="hlt">magnetic</span> field direction on the quantum dynamics in the plane perpendicular to it is taken into account. The new ansatz not only increases the accuracy of the results for energy values and transition strengths obtained so far, but also allows their calculation for <span class="hlt">magnetic</span> field strengths down to B≳BZ, where the adiabatic approximation fails. Restrictions: Intense <span class="hlt">magnetic</span> field strengths are required, since the expansion of the transverse single-particle wave functions using 8 Landau levels will no longer produce accurate results if the scaled <span class="hlt">magnetic</span> field strength parameter βZ=B/BZ becomes much smaller than unity. Unusual features: A huge program speed-up is achieved by making use of pre-calculated binary files. These can be calculated with additional programs provided with this package. Running time: 1-30 min.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...118w3904H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...118w3904H"><span id="translatedtitle">Experimental investigation of inhomogeneities, nanoscopic phase separation, and <span class="hlt">magnetism</span> in arc melted Fe-Cu metals with equal <span class="hlt">atomic</span> ratio of the constituents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hassnain Jaffari, G.; Aftab, M.; Anjum, D. H.; Cha, Dongkyu; Poirier, Gerald; Ismat Shah, S.</p> <p>2015-12-01</p> <p>Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a <span class="hlt">magnetic</span> moment being equal to about 2.13 μB/ Fe <span class="hlt">atom</span> and a bulk like negligible value of coercivity over the temperature range of 5-300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in <span class="hlt">magnetic</span> character. However, for the annealed sample phase separated Fe exhibited homogenous strain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25442538','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25442538"><span id="translatedtitle"><span class="hlt">Magnetic</span> stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa</p> <p>2015-04-01</p> <p>A new dispersive liquid-liquid microextraction, <span class="hlt">magnetic</span> stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS). In this extraction method <span class="hlt">magnetic</span> stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 μg L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples. PMID:25442538</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22200313','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22200313"><span id="translatedtitle">Extraction and preconcentration of trace levels of cobalt using functionalized <span class="hlt">magnetic</span> nanoparticles in a sequential injection lab-on-valve system with detection by electrothermal <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yang; Luo, Xiaoyu; Tang, Jie; Hu, Xiaoya; Xu, Qin; Yang, Chun</p> <p>2012-02-01</p> <p>A new approach to performing extraction and preconcentration employing functionalized <span class="hlt">magnetic</span> nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal <span class="hlt">atomic</span> absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized <span class="hlt">magnetic</span> adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01-5 μg L(-1), and the relative standard deviation was 2.8% at the 0.5 μg L(-1) level (n=11). The limit of detection was 6 ng L(-1) with a sampling frequency of 18 h(-1). The present method has been successfully applied to cobalt determination in water samples and two certified reference materials. PMID:22200313</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..381..138M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..381..138M"><span id="translatedtitle">Preparation of modified <span class="hlt">magnetic</span> nanoparticles as a sorbent for the preconcentration and determination of cadmium ions in food and environmental water samples prior to flame <span class="hlt">atomic</span> absorption spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mirabi, Ali; Dalirandeh, Zeinab; Rad, Ali Shokuhi</p> <p>2015-05-01</p> <p>A new method has been developed for the separation/preconcentration of trace level cadmium ions using diphenyl carbazone/sodium dodecyl sulfate immobilized on <span class="hlt">magnetic</span> nanoparticle Fe3O4 as a new sorbent SPE and their determination by flame <span class="hlt">atomic</span> absorption spectrometry (FAAS). Synthesized nanoparticle was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Various influencing parameters on the separation and preconcentration of trace level cadmium ions such as, pH value, amount of nanoparticles, amount of diphenyl carbazone, condition of eluting solution, the effects of matrix ions were examined. The cadmium ions can be eluted from the modified <span class="hlt">magnetic</span> nanoparticle using 1 mol L-1 HCl as a desorption reagent. The detection limit of this method for cadmium was 3.71 ng ml-1 and the R.S.D. was 0.503% (n=6). The advantages of this new method include rapidity, easy preparation of sorbents and a high concentration factor. The proposed method has been applied to the determination of Cd ions at trace levels in real samples such as, green tea, rice, tobacco, carrot, lettuce, ginseng, spice, tap water, river water, sea water with satisfactory results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/323548','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/323548"><span id="translatedtitle">Global <span class="hlt">warming</span> from HFC</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Johnson, E.</p> <p>1998-11-01</p> <p>Using a variety of public sources, a computer model of hydrofluorocarbon (HFC) refrigerant emissions in the UK has been developed. This model has been used to estimate and project emissions in 2010 under three types of scenarios: (1) business as usual; (2) voluntary agreements to reduce refrigerant leakage; and (3) comprehensive regulations to reduce refrigerant leakage. This resulting forecast is that UK emissions of HFC refrigerants in 2010 will account for 2% to 4% of the UK`s 1990 baseline global <span class="hlt">warming</span> contribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26343434','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26343434"><span id="translatedtitle">In situ emulsification microextraction using a dicationic ionic liquid followed by <span class="hlt">magnetic</span> assisted physisorption for determination of lead prior to micro-sampling flame <span class="hlt">atomic</span> absorption spectrometry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shokri, Masood; Beiraghi, Asadollah; Seidi, Shahram</p> <p>2015-08-19</p> <p>For the first time, a simple and efficient in situ emulsification microextraction method using a dicationic ionic liquid followed by <span class="hlt">magnetic</span> assisted physisorption was presented to determine trace amounts of lead. In this method, 400 μL of 1.0 mol L(-1) lithium bis (trifluoromethylsulfonyl) imide aqueous solution, Li[NTf2], was added into the sample solution containing 100 μL of 1.0 mol L(-1) 1,3-(propyl-1,3-diyl) bis (3-methylimidazolium) chloride, [pbmim]Cl2, to form a water immiscible ionic liquid, [pbmim][NTf2]2. This new in situ formed dicationic ionic liquid was applied as the acceptor phase to extract the lead-ammonium pyrrolidinedithiocarbamate (Pb-APDC) complexes from the sample solution. Subsequently, 30 mg of Fe3O4 <span class="hlt">magnetic</span> nanoparticles (MNPs) were added into the sample solution to collect the fine droplets of [pbmim][NTf2]2, physisorptively. Finally, MNPs were eluted by acetonitrile, separated by an external <span class="hlt">magnetic</span> field and the obtained eluent was subjected to micro-sampling flame <span class="hlt">atomic</span> absorption spectrometry (FAAS) for further analysis. Comparing with other microextraction methods, no special devices and centrifugation step are required. Parameters influencing the extraction efficiency such as extraction time, pH, concentration of chelating agent, amount of MNPs and coexisting interferences were studied. Under the optimized conditions, this method showed high extraction recovery of 93% with low LOD of 0.7 μg L(-1). Good linearity was obtained in the range of 2.5-150 μg L(-1) with determination coefficient (r(2)) of 0.9921. Relative standard deviation (RSD%) for seven repeated measurements at the concentration of 10 μg L(-1) was 4.1%. Finally, this method was successfully applied for determination of lead in some water and plant samples. PMID:26343434</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26953358','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26953358"><span id="translatedtitle">A sensitive <span class="hlt">magnetic</span> nanoparticle-based immunoassay of phosphorylated acetylcholinesterase using protein cage templated lead phosphate for signal amplification with graphite furnace <span class="hlt">atomic</span> absorption spectrometry detection.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liang, Pei; Kang, Caiyan; Yang, Enjian; Ge, Xiaoxiao; Du, Dan; Lin, Yuehe</p> <p>2016-03-21</p> <p>We developed a new <span class="hlt">magnetic</span> nanoparticle sandwich-like immunoassay using protein cage nanoparticles (PCN) for signal amplification together with graphite furnace <span class="hlt">atomic</span> absorption spectrometry (GFAAS) for the quantification of an organophosphorylated acetylcholinesterase adduct (OP-AChE), the biomarker of exposure to organophosphate pesticides (OPs) and nerve agents. OP-AChE adducts were firstly captured by titanium dioxide coated <span class="hlt">magnetic</span> nanoparticles (TiO2-MNPs) from the sample matrixes through metal chelation with phospho-moieties, and then selectively recognized by anti-AChE antibody labeled on PCN which was packed with lead phosphate in its cavity (PCN-anti-AChE). The sandwich-like immunoreaction was performed among TiO2-MNPs, OP-AChE and PCN-anti-AChE to form a TiO2-MNP/OP-AChE/PCN-anti-AChE immunocomplex. The complex could be easily isolated from the sample solution with the help of <span class="hlt">magnet</span>, and the released lead ions from PCN were detected by GFAAS for the quantification of OP-AChE. Greatly enhanced sensitivity was achieved because PCN increased the amount of metal ions in the cavity of each apoferritin. The proposed immunoassay yielded a linear response over a broad range of OP-AChE concentrations from 0.01 nM to 2 nM, with a detection limit of 2 pM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This new method showed an acceptable stability and reproducibility and was validated with OP-AChE spiked human plasma. PMID:26953358</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMGC22A..06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMGC22A..06S"><span id="translatedtitle">Is Global <span class="hlt">Warming</span> Accelerating?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shukla, J.; Delsole, T. M.; Tippett, M. K.</p> <p>2009-12-01</p> <p>A global pattern that fluctuates naturally on decadal time scales is identified in climate simulations and observations. This newly discovered component, called the Global Multidecadal Oscillation (GMO), is related to the Atlantic Meridional Oscillation and shown to account for a substantial fraction of decadal fluctuations in the observed global average sea surface temperature. IPCC-class climate models generally underestimate the variance of the GMO, and hence underestimate the decadal fluctuations due to this component of natural variability. Decomposing observed sea surface temperature into a component due to anthropogenic and natural radiative forcing plus the GMO, reveals that most multidecadal fluctuations in the observed global average sea surface temperature can be accounted for by these two components alone. The fact that the GMO varies naturally on multidecadal time scales implies that it can be predicted with some skill on decadal time scales, which provides a scientific rationale for decadal predictions. Furthermore, the GMO is shown to account for about half of the <span class="hlt">warming</span> in the last 25 years and hence a substantial fraction of the recent acceleration in the rate of increase in global average sea surface temperature. Nevertheless, in terms of the global average “well-observed” sea surface temperature, the GMO can account for only about 0.1° C in transient, decadal-scale fluctuations, not the century-long 1° C <span class="hlt">warming</span> that has been observed during the twentieth century.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22306223','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22306223"><span id="translatedtitle">Design of a self-aligned, wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with 10 nm <span class="hlt">magnetic</span> force microscope resolution</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Karcı, Özgür; Dede, Münir</p> <p>2014-10-01</p> <p>We describe the design of a wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ~12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RScI...85j3705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RScI...85j3705K"><span id="translatedtitle">Design of a self-aligned, wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with 10 nm <span class="hlt">magnetic</span> force microscope resolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karcı, Özgür; Dede, Münir; Oral, Ahmet</p> <p>2014-10-01</p> <p>We describe the design of a wide temperature range (300 mK-300 K) <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ˜12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..93c2504G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..93c2504G"><span id="translatedtitle">Quantum electrodynamics effects on NMR <span class="hlt">magnetic</span> shielding constants of He-like and Be-like <span class="hlt">atomic</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gimenez, Carlos A.; Kozioł, Karol; Aucar, Gustavo A.</p> <p>2016-03-01</p> <p>NMR shielding constants for He- and Be-like <span class="hlt">atomic</span> systems of Ne, Ar, Kr, Xe, and Rn have been calculated at the random-phase-approximation level of approach, including an estimation of QED corrections within the polarization propagator formalism. We show that QED effects enhance electron correlation when Z becomes heavier, which happens with relativistic effects, and also that QED effects become smaller when going from more to less ionized systems. We studied two- and four-electron systems. Then such studies could easily be generalized to other many-electron systems. Results of calculations with our relatively simple model, which includes QED and electron correlation effects on the same theoretical grounds, have a summarized error in the range from 10% (for Ne) up to 24% (for Rn), so that our accuracy is a little lower than for calculations on H-like systems. Our findings should stimulate the development and/or the application of more rigorous formalisms to get more accurate QED corrections to response properties in many-electron systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408224','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408224"><span id="translatedtitle"><span class="hlt">Magnetic</span> dipolar and quadrupolar transitions in two-electron <span class="hlt">atoms</span> under exponential-cosine-screened Coulomb potential</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.</p> <p>2015-03-15</p> <p>A detailed investigation of the <span class="hlt">magnetic</span> dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be{sup 2+}, C{sup 4+}, and O{sup 6+} have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s{sup 2}:{sup 1}S{sup e} → 1sns:{sup 3}S{sup e}{sub 0}, and 1snp:{sup 3}P{sup o}{sub 2} (n = 2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990018501','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990018501"><span id="translatedtitle">Global <span class="hlt">Warming</span> on Triton</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; Buie, M. W.; Pasachoff, J. M.; Babcock, B. A.; McConnochie, T. H.</p> <p>1998-01-01</p> <p>Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global <span class="hlt">warming</span> since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6710038','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6710038"><span id="translatedtitle">Global <span class="hlt">warming</span> challenge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hengeveld, H. )</p> <p>1994-11-01</p> <p>Global <span class="hlt">warming</span> will necessitate significant adjustments in Canadian society and its economy. In 1979, the Canadian federal government created its Canadian Climate Program (CCP) in collaboration with other agencies, institutions, and individuals. It sought to coordinate national efforts to understand global and regional climate, and to promote better use of the emerging knowledge. Much of the CCP-coordinated research into sources and sinks of greenhouse gases interfaces with other national and international programs. Other researchers have become involved in the Northern Wetlands Study, a cooperative United States-Canada initiative to understand the role of huge northern bogs and muskegs in the carbon cycle. Because of the need to understand how the whole, linked climate system works, climate modeling emerged as a key focus of current research. 35 refs., 4 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5930382','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5930382"><span id="translatedtitle"><span class="hlt">Warm</span> waters, bleached corals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roberts, L.</p> <p>1990-10-12</p> <p>Two researchers, Tom Goreau of the Discovery Laboratory in Jamaica and Raymond Hayes of Howard University, claim that they have evidence that nearly clinches the temperature connection to the bleached corals in the Caribbean and that the coral bleaching is an indication of Greenhouse <span class="hlt">warming</span>. The incidents of scattered bleaching of corals, which have been reported for decades, are increasing in both intensity and frequency. The researchers based their theory on increased temperature of the seas measured by satellites. However, some other scientists feel that the satellites measure the temperature of only the top few millimeters of the water and that since corals lie on reefs perhaps 60 to 100 feet below the ocean surface, the elevated temperatures are not significant.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22282887','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22282887"><span id="translatedtitle">Interacting <span class="hlt">warm</span> dark matter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo E-mail: guillermo.palma@usach.cl E-mail: avelino@fisica.ugto.mx</p> <p>2013-05-01</p> <p>We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear λρ{sub m}{sup α}ρ{sub e}{sup β} form, where ρ{sub m} and ρ{sub e} are the energy densities of the dark matter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (λ,α,β) as well as w{sub m} and w{sub e} of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a <span class="hlt">warm</span> dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a <span class="hlt">warm</span> dark matter – phantom dark energy model without interaction, as well as by the ΛCDM model. We find also a large dispersion on the best estimated values of the (λ,α,β) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21372325','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21372325"><span id="translatedtitle">Local <span class="hlt">warming</span>: daily temperature change influences belief in global <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Ye; Johnson, Eric J; Zaval, Lisa</p> <p>2011-04-01</p> <p>Although people are quite aware of global <span class="hlt">warming</span>, their beliefs about it may be malleable; specifically, their beliefs may be constructed in response to questions about global <span class="hlt">warming</span>. Beliefs may reflect irrelevant but salient information, such as the current day's temperature. This replacement of a more complex, less easily accessed judgment with a simple, more accessible one is known as attribute substitution. In three studies, we asked residents of the United States and Australia to report their opinions about global <span class="hlt">warming</span> and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual believed more in and had greater concern about global <span class="hlt">warming</span> than did respondents who thought that day was colder than usual. They also donated more money to a global-<span class="hlt">warming</span> charity if they thought that day seemed warmer than usual. We used instrumental variable regression to rule out some alternative explanations. PMID:21372325</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......115J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......115J"><span id="translatedtitle">Microfabricated Spin Polarized <span class="hlt">Atomic</span> Magnetometers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jimenez Martinez, Ricardo</p> <p></p> <p>Spin polarized <span class="hlt">atomic</span> magnetometers involve the preparation of <span class="hlt">atomic</span> spins and their detection for monitoring <span class="hlt">magnetic</span> fields. Due to the fact that <span class="hlt">magnetic</span> fields are ubiquitous in our world, spin polarized <span class="hlt">atomic</span> magnetometers are used in a wide range of applications from the detection of <span class="hlt">magnetic</span> fields generated by the human heart and brain to the detection of nuclear <span class="hlt">magnetic</span> resonance. In this thesis we developed microfabricated spin polarized <span class="hlt">atomic</span> magnetometers. These sensors are based on optical pumping and spin-exchange collisions between alkali <span class="hlt">atoms</span> and noble gases contained in microfabricated millimeter-scale vapor cells. In the first part of the thesis, we improved different features of current microfabricated optical magnetometers. Specifically, we improved the bandwidth of these devices, without degrading their <span class="hlt">magnetic</span> field sensitivity, by broadening their <span class="hlt">magnetic</span> resonance through spin-exchange collisions between alkali <span class="hlt">atoms</span>. We also implemented all-optical excitation techniques to avoid problems, such as the <span class="hlt">magnetic</span> perturbation of the environment, induced by the radio-frequency fields used in some of these sensors. In the second part of the thesis we demonstrated a microfluidic chip for the optical production and detection of hyperpolarized Xe gas through spin-exchange collisions with optically pumped Rb <span class="hlt">atoms</span>. These devices are critical for the widespread use of spin polarized <span class="hlt">atomic</span> magnetometers in applications requiring simple, compact, low-cost, and portable instrumentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1093274','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1093274"><span id="translatedtitle">Method of performing MRI with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich</p> <p>2013-08-27</p> <p>A method and apparatus are provided for performing an in-situ <span class="hlt">magnetic</span> resonance imaging of an object. The method includes the steps of providing an <span class="hlt">atomic</span> magnetometer, coupling a <span class="hlt">magnetic</span> field generated by <span class="hlt">magnetically</span> resonating samples of the object through a flux transformer to the <span class="hlt">atomic</span> magnetometer and measuring a <span class="hlt">magnetic</span> resonance of the <span class="hlt">atomic</span> magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1080440','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1080440"><span id="translatedtitle">Method of performing MRI with an <span class="hlt">atomic</span> magnetometer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich</p> <p>2012-11-06</p> <p>A method and apparatus are provided for performing an in-situ <span class="hlt">magnetic</span> resonance imaging of an object. The method includes the steps of providing an <span class="hlt">atomic</span> magnetometer, coupling a <span class="hlt">magnetic</span> field generated by <span class="hlt">magnetically</span> resonating samples of the object through a flux transformer to the <span class="hlt">atomic</span> magnetometer and measuring a <span class="hlt">magnetic</span> resonance of the <span class="hlt">atomic</span> magnetometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992AIPC..247..222C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992AIPC..247..222C"><span id="translatedtitle">Policy implications of greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coppock, Rob</p> <p>1992-03-01</p> <p>A study panel of the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine recently issued the report Policy Implications of Greenhouse <span class="hlt">Warming</span>. That report examined relevant scientific knowldeg and evidence about the potential of greenhouse <span class="hlt">warming</span>, and assayed actions that could slow the onset of <span class="hlt">warming</span> (mitigation policies) or help human and natural systems of plants and animals adapt to climatic changes (adaptation policies). The panel found that, even given the considerable uncertainties knowledge of the relevant phenomena, greenhouse <span class="hlt">warming</span> poses a threat sufficient to merit prompt action. People in this country could probably adapt to the changes likely to accompany greenhouse <span class="hlt">warming</span>. The costs, however, could be substantial. Investment in mitigation acts as insurance protection against the great uncertainties and the possibility of dramatic surprises. The panel found mitigation options that could reduce U.S. emissions by an estimated 10 to 40 percent at modest cost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MAR.X1014K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MAR.X1014K"><span id="translatedtitle">Design of a Self-Aligned, High Sensitivity Fiber Fabry-Perot Interferometer for Low Temperature <span class="hlt">Atomic</span> Force Microscope/<span class="hlt">Magnetic</span> Force Microscope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karci, Ozgur; Dede, Munir; Oral, Ahmet</p> <p>2012-02-01</p> <p>We describe the design of a high sensitivity fiber Fabry-Perot interferometer for low temperature <span class="hlt">atomic</span> force microscope/<span class="hlt">magnetic</span> force microscope. This is a self-aligned system utilizing an alignment chip and eliminating all tedious alignment procedures. Our interferometer cavity is composed of a cleaved fiber, which is coated using dielectric to increase the reflectivity of laser from fiber-air interface, and a cantilever. 50 percent of the incident laser beam is reflected at the end of the fiber. The transmitted light propagates from the fiber end and hits the cantilever. Multiple reflections occur between cantilever and the fiber then the beams go into the fiber again. These two beams interfere and generate a photocurrent at the PD which is used for deflection measurement. We designed a special stick-slip coarse approach mechanism using piezoelectric tube scanner of the microscope. We have measured 8fm per square root Hz noise level at 300K, while the shot noise limit was 2fm per square root Hz. Our previous Michelson interferometer design had 20 fm per square root Hz noise level and gave better than 10nm MFM resolution on hard disk. Our goal is to further enhance the noise levels and achieve 6 nm resolution for LT-MFM with this new interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5371673','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5371673"><span id="translatedtitle">Laser-<span class="hlt">magnetic</span>-resonance detection of magnesium <span class="hlt">atoms</span> in the metastable /sup 3/P/sub 0,ts1,ts2/ states</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Inguscio, M.; Leopold, K.R.; Murray, J.S.; Evenson, K.M.</p> <p>1985-09-01</p> <p>Transitions between fine-structure levels of the metastable (3s3p/sup 3/P) state of magnesium have been observed by means of the highly sensitive technique of far-infrared laser-<span class="hlt">magnetic</span>-resonance spectroscopy. The g factors for the /sup 3/P/sub 1/ and /sup 3/P/sub 2/ levels are 1.50111(16) and 1.50102(16), respectively, and the /sup 3/P/sub 1/--/sup 3/P/sub 2/ energy separation is1 220575.1(33) MHz. The observed g factors show good agreement with the predicted values. This stands in marked contrast to similar results for <span class="hlt">atomic</span> silicon (/sup 3/P) and aluminum (/sup 2/P), for which the theoretical and experimental g factors differ substantially. The value of the /sup 3/P/sub 1/--/sup 3/P/sub 2/ energy separation is improved by nearly 2 orders of magnitude over the optical value and is of sufficient accuracy to permit possible extraterrestrial identification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080030145&hterms=hydro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydro','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080030145&hterms=hydro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydro"><span id="translatedtitle">Explaining <span class="hlt">Warm</span> Coronal Loops</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros</p> <p>2008-01-01</p> <p>One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense <span class="hlt">warm</span> loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7794B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7794B"><span id="translatedtitle">Defining Sudden Stratospheric <span class="hlt">Warmings</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butler, Amy; Seidel, Dian; Hardiman, Steven; Butchart, Neal; Birner, Thomas; Match, Aaron</p> <p>2015-04-01</p> <p>The general form of the definition for Sudden Stratospheric <span class="hlt">Warmings</span> (SSWs) is largely agreed to be a reversal of the temperature gradient and of the zonal circulation polewards of 60° latitude at the 10 hPa level, as developed by the World Meteorological Organization (WMO) in the 1960s and 1970s. However, the details of the definition and its calculation are ambiguous, resulting in inconsistent classifications of SSW events. These discrepancies are problematic for understanding the observed frequency and statistical relationships with SSWs, and for maintaining a robust metric with which to assess wintertime stratospheric variability in observations and climate models. To provide a basis for community-wide discussion, we examine how the SSW definition has changed over time and how sensitive the detection of SSWs is to the definition used. We argue that the general form of the SSW definition should be clarified to ensure that it serves current research and forecasting purposes, and propose possible ways to update the definition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008CoPhC.178..301C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008CoPhC.178..301C"><span id="translatedtitle">POTHMF: A program for computing potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chuluunbaatar, O.; Gusev, A. A.; Gerdt, V. P.; Rostovtsev, V. A.; Vinitsky, S. I.; Abrashkevich, A. G.; Kaschiev, M. S.; Serov, V. V.</p> <p>2008-02-01</p> <p>A FORTRAN 77 program is presented which calculates with the relative machine precision potential curves and matrix elements of the coupled adiabatic radial equations for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field. The potential curves are eigenvalues corresponding to the angular oblate spheroidal functions that compose adiabatic basis which depends on the radial variable as a parameter. The matrix elements of radial coupling are integrals in angular variables of the following two types: product of angular functions and the first derivative of angular functions in parameter, and product of the first derivatives of angular functions in parameter, respectively. The program calculates also the angular part of the dipole transition matrix elements (in the length form) expressed as integrals in angular variables involving product of a dipole operator and angular functions. Moreover, the program calculates asymptotic regular and irregular matrix solutions of the coupled adiabatic radial equations at the end of interval in radial variable needed for solving a multi-channel scattering problem by the generalized R-matrix method. Potential curves and radial matrix elements computed by the POTHMF program can be used for solving the bound state and multi-channel scattering problems. As a test desk, the program is applied to the calculation of the energy values, a short-range reaction matrix and corresponding wave functions with the help of the KANTBP program. Benchmark calculations for the known photoionization cross-sections are presented. Program summaryProgram title:POTHMF Catalogue identifier:AEAA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAA_v1_0.html Program obtainable from:CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions:Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.:8123 No. of bytes in distributed program, including test data, etc.:131 396 Distribution format:tar.gz Programming language:FORTRAN 77 Computer:Intel Xeon EM64T, Alpha 21264A, AMD Athlon MP, Pentium IV Xeon, Opteron 248, Intel Pentium IV Operating system:OC Linux, Unix AIX 5.3, SunOS 5.8, Solaris, Windows XP RAM:Depends on the number of radial differential equations; the number and order of finite elements; the number of radial points. Test run requires 4 MB Classification:2.5 External routines:POTHMF uses some Lapack routines, copies of which are included in the distribution (see README file for details). Nature of problem:In the multi-channel adiabatic approach the Schrödinger equation for a hydrogen-like <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field of strength γ ( γ=B/B, B≅2.35×10 T is a dimensionless parameter which determines the field strength B) is reduced by separating the radial coordinate, r, from the angular variables, (θ,φ), and using a basis of the angular oblate spheroidal functions [3] to a system of second-order ordinary differential equations which contain first-derivative coupling terms [4]. The purpose of this program is to calculate potential curves and matrix elements of radial coupling needed for calculating the low-lying bound and scattering states of hydrogen-like <span class="hlt">atoms</span> in a homogeneous <span class="hlt">magnetic</span> field of strength 0<γ⩽1000 within the adiabatic approach [5]. The program evaluates also asymptotic regular and irregular matrix radial solutions of the multi-channel scattering problem needed to extract from the R-matrix a required symmetric shortrange open-channel reaction matrix K [6] independent from matching point [7]. In addition, the program computes the dipole transition matrix elements in the length form between the basis functions that are needed for calculating the dipole transitions between the low-lying bound and scattering states and photoionization cross sections [8]. Solution method:The angular oblate spheroidal eigenvalue problem depending on the radial variable is solved using a series expansion in the Legendre polynomials [3]. The resulting tridiagonal symmetric algebraic eigenvalue problem for the evaluation of selected eigenvalues, i.e. the potential curves, is solved by the LDLT factorization using the DSTEVR program [2]. Derivatives of the eigenfunctions with respect to the radial variable which are contained in matrix elements of the coupled radial equations are obtained by solving the inhomogeneous algebraic equations. The corresponding algebraic problem is solved by using the LDLT factorization with the help of the DPTTRS program [2]. Asymptotics of the matrix elements at large values of radial variable are computed using a series expansion in the associated Laguerre polynomials [9]. The corresponding matching points between the numeric and asymptotic solutions are found automatically. These asymptotics are used for the evaluation of the asymptotic regular and irregular matrix radial solutions of the multi-channel scattering problem [7]. As a test desk, the program is applied to the calculation of the energy values of the ground and excited bound states and reaction matrix of multi-channel scattering problem for a hydrogen <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field using the KANTBP program [10]. Restrictions:The computer memory requirements depend on: the number of radial differential equations; the number and order of finite elements; the total number of radial points. Restrictions due to dimension sizes can be changed by resetting a small number of PARAMETER statements before recompiling (see Introduction and listing for details). Running time:The running time depends critically upon: the number of radial differential equations; the number and order of finite elements; the total number of radial points on interval [r,r]. The test run which accompanies this paper took 7 s required for calculating of potential curves, radial matrix elements, and dipole transition matrix elements on a finite-element grid on interval [ r=0, r=100] used for solving discrete and continuous spectrum problems and obtaining asymptotic regular and irregular matrix radial solutions at r=100 for continuous spectrum problem on the Intel Pentium IV 2.4 GHz. The number of radial differential equations was equal to 6. The accompanying test run using the KANTBP program took 2 s for solving discrete and continuous spectrum problems using the above calculated potential curves, matrix elements and asymptotic regular and irregular matrix radial solutions. Note, that in the accompanied benchmark calculations of the photoionization cross-sections from the bound states of a hydrogen <span class="hlt">atom</span> in a homogeneous <span class="hlt">magnetic</span> field to continuum we have used interval [ r=0, r=1000] for continuous spectrum problem. The total number of radial differential equations was varied from 10 to 18. References:W.H. Press, S.A. Teukolsky, W.T. Vetterling, B.P. Flannery, Numerical Recipes: The Art of Scientific Computing, Cambridge University Press, Cambridge, 1986. http://www.netlib.org/lapack/. M. Abramovits, I.A. Stegun, Handbook of Mathematical Functions, Dover, New York, 1965. U. Fano, Colloq. Int. C.N.R.S. 273 (1977) 127; A.F. Starace, G.L. Webster, Phys. Rev. A 19 (1979) 1629-1640; C.V. Clark, K.T. Lu, A.F. Starace, in: H.G. Beyer, H. Kleinpoppen (Eds.), Progress in <span class="hlt">Atomic</span> Spectroscopy, Part C, Plenum, New York, 1984, pp. 247-320; U. Fano, A.R.P. Rau, <span class="hlt">Atomic</span> Collisions and Spectra, Academic Press, Florida, 1986. M.G. Dimova, M.S. Kaschiev, S.I. Vinitsky, J. Phys. B 38 (2005) 2337-2352; O. Chuluunbaatar, A.A. Gusev, V.L. Derbov, M.S. Kaschiev, V.V. Serov, T.V. Tupikova, S.I. Vinitsky, Proc. SPIE 6537 (2007) 653706-1-18. M.J. Seaton, Rep. Prog. Phys. 46 (1983) 167-257. M. Gailitis, J. Phys. B 9 (1976) 843-854; J. Macek, Phys. Rev. A 30 (1984) 1277-1278; S.I. Vinitsky, V.P. Gerdt, A.A. Gusev, M.S. Kaschiev, V.A. Rostovtsev, V.N. Samoylov, T.V. Tupikova, O. Chuluunbaatar, Programming and Computer Software 33 (2007) 105-116. H. Friedrich, Theoretical <span class="hlt">Atomic</span> Physics, Springer, New York, 1991. R.J. Damburg, R.Kh. Propin, J. Phys. B 1 (1968) 681-691; J.D. Power, Phil. Trans. Roy. Soc. London A 274 (1973) 663-702. O. Chuluunbaatar, A.A. Gusev, A.G. Abrashkevich, A. Amaya-Tapia, M.S. Kaschiev, S.Y. Larsen, S.I. Vinitsky, Comput. Phys. Comm. 177 (2007) 649-675.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4189960','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4189960"><span id="translatedtitle">Recent <span class="hlt">Warming</span> of Lake Kivu</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.</p> <p>2014-01-01</p> <p>Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the <span class="hlt">warming</span> trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is <span class="hlt">warming</span> at the rate of 0.12°C per decade, which matches the <span class="hlt">warming</span> rates in other East African lakes. Temperatures increase throughout the entire water column. Though <span class="hlt">warming</span> is strongest near the surface, <span class="hlt">warming</span> rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the <span class="hlt">warming</span> in deeper waters. The <span class="hlt">warming</span> trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25295730','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25295730"><span id="translatedtitle">Recent <span class="hlt">warming</span> of lake Kivu.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E</p> <p>2014-01-01</p> <p>Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the <span class="hlt">warming</span> trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is <span class="hlt">warming</span> at the rate of 0.12°C per decade, which matches the <span class="hlt">warming</span> rates in other East African lakes. Temperatures increase throughout the entire water column. Though <span class="hlt">warming</span> is strongest near the surface, <span class="hlt">warming</span> rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the <span class="hlt">warming</span> in deeper waters. The <span class="hlt">warming</span> trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22273827','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22273827"><span id="translatedtitle">Change in <span class="hlt">magnetic</span> and structural properties of FeRh thin films by gold cluster ion beam irradiation with the energy of 1.67 MeV/<span class="hlt">atom</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Koide, T.; Iwase, A.; Saitoh, Y.; Sakamaki, M.; Amemiya, K.; Matsui, T.</p> <p>2014-05-07</p> <p>The effect of energetic cluster ion beam irradiation on <span class="hlt">magnetic</span> and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold <span class="hlt">atoms</span> with the energy of 1.67 MeV/gold <span class="hlt">atom</span>. Saturation <span class="hlt">magnetization</span> of the sample irradiated with Au3 cluster ion beam (280 emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240 emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray <span class="hlt">magnetic</span> circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced <span class="hlt">magnetization</span> of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation <span class="hlt">magnetization</span>, even if the same irradiation energy is deposited in the samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20991195','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20991195"><span id="translatedtitle">Spatially resolved photoionization of ultracold <span class="hlt">atoms</span> on an <span class="hlt">atom</span> chip</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kraft, S.; Guenther, A.; Fortagh, J.; Zimmermann, C.</p> <p>2007-06-15</p> <p>We report on photoionization of ultracold <span class="hlt">magnetically</span> trapped Rb <span class="hlt">atoms</span> on an <span class="hlt">atom</span> chip. The <span class="hlt">atoms</span> are trapped at 5 {mu}K in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 {mu}m, two laser beams are focused onto a fraction of the <span class="hlt">atomic</span> cloud. A first laser beam with a wavelength of 778 nm excites the <span class="hlt">atoms</span> via a two-photon transition to the 5D level. With a fiber laser at 1080 nm the excited <span class="hlt">atoms</span> are photoionized. Ionization leads to depletion of the <span class="hlt">atomic</span> density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is suitable not only to investigate mixtures of Bose-Einstein condensates and ions but also for single-<span class="hlt">atom</span> detection on an <span class="hlt">atom</span> chip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25902494','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25902494"><span id="translatedtitle">Amplified Arctic <span class="hlt">warming</span> by phytoplankton under greenhouse <span class="hlt">warming</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho</p> <p>2015-05-12</p> <p>Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future <span class="hlt">warming</span> experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse <span class="hlt">warming</span> can amplify Arctic surface <span class="hlt">warming</span> considerably. The <span class="hlt">warming</span>-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton <span class="hlt">warms</span> the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic <span class="hlt">warming</span> further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4434777','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4434777"><span id="translatedtitle">Amplified Arctic <span class="hlt">warming</span> by phytoplankton under greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho</p> <p>2015-01-01</p> <p>Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical–ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future <span class="hlt">warming</span> experiments using a fully coupled ocean−atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse <span class="hlt">warming</span> can amplify Arctic surface <span class="hlt">warming</span> considerably. The <span class="hlt">warming</span>-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton <span class="hlt">warms</span> the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic <span class="hlt">warming</span> further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes. PMID:25902494</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAsGe...4..154A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAsGe...4..154A"><span id="translatedtitle"><span class="hlt">Magnetic</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.</p> <p>2015-06-01</p> <p>The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and <span class="hlt">magnetic</span> data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25401364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25401364"><span id="translatedtitle"><span class="hlt">Atomic</span> lighthouse effect.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Máximo, C E; Kaiser, R; Courteille, Ph W; Bachelard, R</p> <p>2014-11-01</p> <p>We investigate the deflection of light by a cold <span class="hlt">atomic</span> cloud when the light-matter interaction is locally tuned via the Zeeman effect using <span class="hlt">magnetic</span> field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease in <span class="hlt">magnetic</span> field efficiency. PMID:25401364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..DMP.S4006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..DMP.S4006C"><span id="translatedtitle">Progress towards trapping of <span class="hlt">atomic</span> hydrogen isotopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chavez, Isaac; Libson, Adam; Mazur, Tom; Majors, Julia; Raizen, Mark</p> <p>2009-05-01</p> <p>Using a series of pulsed electromagnetic coils (<span class="hlt">atomic</span> coilgun) we can stop supersonic beams of paramagnetic <span class="hlt">atoms</span> and molecules. We will employ the coilgun method to stop and trap supersonic beams of hydrogen isotopes. The slowed <span class="hlt">atoms</span> will be trapped in a quadrupole <span class="hlt">magnetic</span> trap where single-photon <span class="hlt">atomic</span> cooling will be applied. Further applications will be discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NatGe...5..369S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NatGe...5..369S"><span id="translatedtitle">Glaciology: Repeat <span class="hlt">warming</span> in Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Benjamin E.</p> <p>2012-06-01</p> <p>Greenland's glaciers have lost significant amounts of ice over the past decade. Rediscovered historical images of the ice margin show a record of southeast Greenland's response to the last major <span class="hlt">warming</span> event in the 1930s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1084068','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1084068"><span id="translatedtitle"><span class="hlt">Magnetic</span> nanohole superlattices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Liu, Feng</p> <p>2013-05-14</p> <p>A <span class="hlt">magnetic</span> material is disclosed including a two-dimensional array of carbon <span class="hlt">atoms</span> and a two-dimensional array of nanoholes patterned in the two-dimensional array of carbon <span class="hlt">atoms</span>. The <span class="hlt">magnetic</span> material has long-range <span class="hlt">magnetic</span> ordering at a temperature below a critical temperature Tc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.203..605D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.203..605D"><span id="translatedtitle">Transition <span class="hlt">warming</span> and cooling remanences in pyrrhotite and hematite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunlop, David J.</p> <p>2015-10-01</p> <p><span class="hlt">Magnetic</span> minerals acquire a remanent <span class="hlt">magnetization</span> when cooled or <span class="hlt">warmed</span> in an applied field H through a phase transition. This paper reports the first observations of transition cooling and <span class="hlt">warming</span> remanent <span class="hlt">magnetizations</span> (TrCRM and TrWRM) in pyrrhotite (Fe7S8) and hematite (αFe2O3), with phase transitions at 32 K (Besnus transition) and 250 K (Morin transition). TrWRM was produced by <span class="hlt">warming</span> in a 2 mT field from 10 to 300 K and TrCRM by cooling in 2 mT from 300 to 10 K. In both experiments, <span class="hlt">magnetization</span> M was measured at 5 K intervals. The largest changes in M occurred over a 20 K interval flanking the Besnus or Morin transition but substantial changes also occurred away from any transition, presumably due to continuous changes in anisotropy. The triclinic low-temperature phase of pyrrhotite has high remanence efficiency compared to the room-temperature monoclinic phase. When H was zeroed at 300 K, only 35-40% of M survived as TrWRM, but in TrCRM experiments when H was zeroed at 10 K, practically 100% of M was preserved. After zero-field cooling to 10 K, 50-60% of TrWRM was retained but <15% of TrCRM survived zero-field <span class="hlt">warming</span> to 300 K. In hematite, both TrWRM of the room-temperature spin-canted phase and TrCRM of the low-temperature defect phase exist, as shown by net remanence production following complete <span class="hlt">warming</span>-cooling or cooling-<span class="hlt">warming</span> cycles between 10 and 300 K. Details of remanence acquisition/demagnetization in crossing the Morin transition could not be resolved, however. Symmetries were observed for both minerals. Single-domain size pyrrhotite crystals had mirror-image field-off and field-on <span class="hlt">warming</span> curves below 32 K, during TrWRM production/TrCRM loss at the 32 K transition, and up to ≈150 K. Submicron single-domain hematite had almost complete symmetry between field-off and field-on curves during cooling as well as <span class="hlt">warming</span>, both below and above the Morin transition but not in the transition region itself. This is the first time that mirror-image symmetries, observed previously for pseudo-single-domain and multidomain magnetite, have been documented for mineral grains in a single-domain state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22412952','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22412952"><span id="translatedtitle">Experimental evidence of <span class="hlt">warm</span> electron populations in magnetron sputtering plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sahu, B. B. Han, Jeon G.; Kim, Hye R.; Ishikawa, K.; Hori, M.</p> <p>2015-01-21</p> <p>This work report on the results obtained using the Langmuir probe (LP) measurements in high-power dc magnetron sputtering discharges. Data show clear evidence of two electron components, such as <span class="hlt">warm</span> and bulk electrons, in the sputtering plasma in a <span class="hlt">magnetic</span> trap. We have also used optical emission spectroscopy diagnostic method along with LP to investigate the plasma production. Data show that there is a presence of low-frequency oscillations in the 23?MHz range, which are expected to be generated by high-frequency waves. Analysis also suggests that the <span class="hlt">warm</span> electrons, in the plasmas, can be formed due to the collisionless Landau damping of the bulk electrons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...580A..77R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...580A..77R"><span id="translatedtitle"><span class="hlt">Warm</span> and optically thick dissipative coronae above accretion disks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Różańska, A.; Malzac, J.; Belmont, R.; Czerny, B.; Petrucci, P.-O.</p> <p>2015-08-01</p> <p>Context. In past years, several observations of AGN and X-ray binaries suggested the existence of a <span class="hlt">warm</span> (T ~ 0.5 - 1 keV) and optically thick (τcor ~ 10 - 20) corona covering the inner parts of the accretion disk. These properties are directly derived from spectral fitting in UV to soft-X-rays using Comptonization models. However, whether such a medium can be both in radiative and hydrostatic equilibrium with an accretion disk is still uncertain. Aims: We investigate the properties of such <span class="hlt">warm</span>, optically thick coronae and put constraints on their existence. Methods: We solve the radiative transfer equation for grey atmosphere analytically in a pure scattering medium, including local dissipation as an additional heating term in the <span class="hlt">warm</span> corona. The temperature profile of the <span class="hlt">warm</span> corona is calculated assuming that it is cooled by Compton scattering, with the underlying dissipative disk providing photons to the corona. Results: Our analytic calculations show that a dissipative thick corona (τcor in the range 10-12) on top of a standard accretion disk can reach temperatures of the order of 0.5-1 keV in its upper layers provided that the disk is passive. However, in the absence of strong <span class="hlt">magnetic</span> fields, the requirement of a Compton cooled corona in hydrostatic equilibrium in the vertical direction sets an upper limit on the Thomson optical depth τcor ≲ 5. We show that this value cannot be exceeded independently of the accretion disk parameters. However, <span class="hlt">magnetic</span> pressure can extend this result to larger optical depths. Namely, a dissipative corona might have an optical depth up to ~20 when the <span class="hlt">magnetic</span> pressure is 100 times higher than the gas pressure. Conclusions: The observation of <span class="hlt">warm</span> coronae with Thomson depth larger than ≃5 puts tight constraints on the physics of the accretion disk/corona systems and requires either strong <span class="hlt">magnetic</span> fields or vertical outflows to stabilize the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DMP.K1011M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DMP.K1011M"><span id="translatedtitle">Simulating narrow nonlinear resonance features for magnetometry in compact cold <span class="hlt">atom</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, David; Robinson, Jenn; Kunz, Paul; Quraishi, Qudsia</p> <p>2015-05-01</p> <p>We are investigating cold <span class="hlt">atom</span> magnetometry applications and have developed a numeric model of Electromagnetically Induced Absorption (EIA) and Nonlinear Magneto-Optical Rotation (NMOR) for degenerate two-level systems. While most EIA and NMOR research is done in <span class="hlt">warm</span> vapors, cold <span class="hlt">atoms</span> avoid Doppler broadening and better isolate the various optical pumping mechanisms involved. Our model focuses on the effect of transverse <span class="hlt">magnetic</span> fields on both EIA and NMOR features and shows that critical points of both yield quantitative measures of the magnitude and direction of the transverse field. This dependence reveals the underlying optical pumping mechanisms and makes possible a single, in-situ measurement of the background <span class="hlt">magnetic</span> field zero to the sub-milligauss level, reducing background fields to enhance sub-Doppler cooling and collectively-enhanced neutral-<span class="hlt">atom</span> quantum memory lifetimes. Separately, we are pursuing experimental measurements on the relationship between EIA and NMOR in a compact cold <span class="hlt">atom</span> apparatus. To improve the system's capabilities we are designing our next-generation <span class="hlt">atom</span> chip to reduce system size and employ versatile geometries enabling multi-site trapping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21393778','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21393778"><span id="translatedtitle"><span class="hlt">Magnetic</span> nanostructures.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bennemann, K</p> <p>2010-06-23</p> <p>Characteristic results of <span class="hlt">magnetism</span> in small particles, thin films and tunnel junctions are presented. As a consequence of the reduced <span class="hlt">atomic</span> coordination in small clusters and thin films the electronic states and density of states are modified. Thus, <span class="hlt">magnetic</span> moments and <span class="hlt">magnetization</span> are affected. Generally, in clusters and thin films <span class="hlt">magnetic</span> anisotropy plays a special role. In tunnel junctions the interplay of <span class="hlt">magnetism</span>, spin currents and superconductivity are of particular interest. In ring-like mesoscopic systems Aharonov-Bohm-induced currents are studied. Results are given for single transition metal clusters, cluster ensembles, thin films, mesoscopic structures and tunnel systems. PMID:21393778</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B11E..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B11E..03B"><span id="translatedtitle">Soil <span class="hlt">Warming</span> and Carbon Release: Varying Patterns of Organic Matter Breakdown Across Five Ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Billings, S. A.; Barich, D.; Munson, E.</p> <p>2008-12-01</p> <p>Our understanding of the mechanisms governing soil organic carbon (SOC) retention vs. loss as CO2 in the future suffers from an inability to predict how mineralization of labile vs. recalcitrant SOC will proceed with <span class="hlt">warming</span>. Incubation and field studies of soil <span class="hlt">warming</span> have resulted in conflicting conclusions about how multiple SOC pools will respond to rising temperatures. In this study, we explore SOC transformations in a long-term incubation with <span class="hlt">warming</span> from five North American ecosystems by assessing respired CO2 and solid state 13C nuclear <span class="hlt">magnetic</span> resonance (NMR) spectra of non-incubated and cool vs. <span class="hlt">warm</span> incubated soils. We also quantified extra-cellular enzyme activities (EEA) late in the incubation to assess how relatively slow-turnover SOC pools responded to <span class="hlt">warming</span>. Soils from a cool temperate forest, a <span class="hlt">warm</span> temperate forest, and a temperate grassland released an average of 95% more CO2 when <span class="hlt">warmed</span> by the end of the 200 d incubation. Soils from a boreal forest and acidic arctic tundra released slightly more CO2 with <span class="hlt">warming</span> during the first 20 d of the incubation, but after day 20 and until day 200 CO2 released by <span class="hlt">warmed</span> soils was equivalent to the control soils. NMR spectra and EEA data suggest varying responses of these ecosystems' SOC pools to <span class="hlt">warming</span>. Arctic tundra soils did not experience a change in the kinds of C compounds mineralized with <span class="hlt">warming</span>, yet EEA data indicate greater acquisition of C from phenolic compounds. Boreal forest soil NMR spectra suggest greater net humification with <span class="hlt">warming</span>, with only slight increases in enzymatic C acquisition. These soils may have experienced an increase in C use efficiency with <span class="hlt">warming</span> that resulted in acquired C not being "wasted" on respiration. Cool temperate forest soils exhibited no change in the kinds of C accessed by microbes with <span class="hlt">warming</span>, as revealed via NMR, in spite of these soils' greater C acquisition and respiration with <span class="hlt">warming</span>. Grassland soils experienced an increase in humification with <span class="hlt">warming</span>, associated with an increase in CO2 released. <span class="hlt">Warm</span> temperate forest soils, in contrast, exhibited less humification with <span class="hlt">warming</span>. These data suggest that changing microbial C use efficiency with <span class="hlt">warming</span> is an important and relatively unexplored determinant governing the net influence of <span class="hlt">warming</span> on SOC transformations and eventual CO2 release.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DMP.K1125Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DMP.K1125Y"><span id="translatedtitle">Nuclear quantum dynamics in <span class="hlt">warm</span> dense hydrogen</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Jianmin; Kang, Dongdong; Dai, Jiayu; Sun, Huayang</p> <p>2014-05-01</p> <p>Quantum dynamics is a challenging problem in <span class="hlt">atomic</span> and molecular dynamics. Ionic and electronic transport behaviors are strongly dependent on their dynamics, whose key physics is the scattering or collisions between particles. We usually consider only the quantum effects of electrons, but neglect the quantum effects of ions. Here, we show that the nuclear quantum effects can induce quantum tunneling in <span class="hlt">warm</span> dense hydrogen, resulting in larger ionic diffusions and less electronic transport such as electrical and thermal conductivities. In order to study the nuclear quantum dynamics, we modify the sampling formula in path integral molecular dynamics (centriod molecular dynamics, CMD). Using the new sampling, the tunneling probability from CMD is consistent with the results of WKB approximation and full quantum mechanical calculations near the classical limit. The significant quantum delocalization of ions introduces expressively different scattering cross section between protons compared with classical particle treatments, which can explain the large alterability of transport behaviors. The complex behavior shows that NQEs cannot be neglected for dense hydrogen even in the <span class="hlt">warm</span> dense regime, which would be important for the giant planets and inertial confinement fusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21020564','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21020564"><span id="translatedtitle">Calibration of a single-<span class="hlt">atom</span> detector for <span class="hlt">atomic</span> microchips</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stibor, A.; Kraft, S.; Komma, D.; Guenther, A.; Fortagh, J.; Zimmermann, C.; Campey, T.; Vale, C. J.; Rubinsztein-Dunlop, H.</p> <p>2007-09-15</p> <p>We experimentally investigate a scheme for detecting single <span class="hlt">atoms</span> <span class="hlt">magnetically</span> trapped on an <span class="hlt">atom</span> chip. The detector is based on the photoionization of <span class="hlt">atoms</span> and the subsequent detection of the generated ions. We describe the characterization of the ion detector with emphasis on its calibration via the correlation of ions with simultaneously generated electrons. A detection efficiency of 47.8{+-}2.6 % is measured, which is useful for single-<span class="hlt">atom</span> detection, and close to the limit allowing <span class="hlt">atom</span> counting with sub-Poissonian uncertainty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22483111','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22483111"><span id="translatedtitle"><span class="hlt">Magnetic</span>-field-induced rotation of light with orbital angular momentum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shi, Shuai; Ding, Dong-Sheng Zhou, Zhi-Yuan; Li, Yan; Zhang, Wei; Shi, Bao-Sen</p> <p>2015-06-29</p> <p>Light carrying orbital angular momentum (OAM) has attractive applications in the fields of precise optical measurements and high capacity optical communications. We study the rotation of a light beam propagating in <span class="hlt">warm</span> {sup 87}Rb <span class="hlt">atomic</span> vapor using a method based on <span class="hlt">magnetic</span>-field-induced circular birefringence. The dependence of the rotation angle on the <span class="hlt">magnetic</span> field makes it appropriate for weak <span class="hlt">magnetic</span> field measurements. We quote a detailed theoretical description that agrees well with the experimental observations. The experiment shown here provides a method to measure the <span class="hlt">magnetic</span> field intensity precisely and expands the application of OAM-carrying light. This technique has advantage in measurement of <span class="hlt">magnetic</span> field weaker than 0.5 G, and the precision we achieved is 0.8 mG.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC32A..02F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC32A..02F"><span id="translatedtitle">The Great <span class="hlt">Warming</span> Brian Fagan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fagan, B. M.</p> <p>2010-12-01</p> <p>The Great <span class="hlt">Warming</span> is a journey back to the world of a thousand years ago, to the Medieval <span class="hlt">Warm</span> Period. Five centuries of irregular <span class="hlt">warming</span> from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of <span class="hlt">warming</span> on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great <span class="hlt">Warming</span> argues that the <span class="hlt">warm</span> centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global <span class="hlt">warming</span>, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatPh..11..998C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatPh..11..998C"><span id="translatedtitle">Quantum transport in ultracold <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chien, Chih-Chun; Peotta, Sebastiano; di Ventra, Massimiliano</p> <p>2015-12-01</p> <p>Ultracold <span class="hlt">atoms</span> confined by engineered <span class="hlt">magnetic</span> or optical potentials are ideal to study phenomena otherwise difficult to realize or probe in the solid state, thanks to the ability to control the <span class="hlt">atomic</span> interaction strength, number of species, density and geometry. Here, we review quantum transport phenomena in <span class="hlt">atomic</span> gases that mirror and can either better elucidate or show fundamental differences with respect to those observed in mesoscopic and nanoscopic systems. We discuss the significant progress in transport experiments in <span class="hlt">atomic</span> gases, the similarities and differences between transport in cold <span class="hlt">atoms</span> and in condensed matter systems, and survey theoretical predictions that are difficult to verify in conventional set-ups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988PhLB..201..192D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988PhLB..201..192D"><span id="translatedtitle">Hadronic lamb shift in antiprotonic <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Decker, Roger; Martinis, Mladen</p> <p>1988-02-01</p> <p>We estimate the difference between the anomalous <span class="hlt">magnetic</span> moments of bound and free antiprotons and discuss its relevance in the <span class="hlt">magnetic</span> fine structure of antiprotonic <span class="hlt">atoms</span>. Permanent address: Institute Ruder Bòskovic, YU-41001 Zagreb, Yugoslavia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RaPC..110..119P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RaPC..110..119P"><span id="translatedtitle">A study of K shell X-ray intensity ratios of NixCr1-x alloys in external <span class="hlt">magnetic</span> field and determination of effective <span class="hlt">atomic</span> numbers of these alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perişanoğlu, Ufuk; Demir, Lütfü</p> <p>2015-05-01</p> <p>In this study, the effect of external <span class="hlt">magnetic</span> field on the Kβ/Kα X-ray intensity ratios of various alloy compositions of Ni-Cr transition metal alloys has been investigated. The Kα and Kβ emission spectra of Ni, Cr and NixCr1-x (x=0.40; 0.50; 0.60; 0.80) alloys were measured by using a Si (Li) solid-state detector. Kβ/Kα X-ray intensity ratios of Ni, Cr and NixCr1-x alloys without <span class="hlt">magnetic</span> field and in 0.5 and 1 T external <span class="hlt">magnetic</span> field have been measured following excitation by 59.5 keV γ-rays from a 200 mCi241Am radioisotope point source. When the experimental data obtained in external <span class="hlt">magnetic</span> field have been compared with data without external <span class="hlt">magnetic</span> field, deviations have been observed in Kβ/Kα X-ray intensity ratios for Ni and Cr in different alloy compositions. Thus, results of these measurements have shown that Kβ/Kα X-ray intensity ratios of Ni and Cr in NixCr1-x alloys are dependent on the external <span class="hlt">magnetic</span> field. Also the total mass attenuation coefficients for pure 3d transition metals and their alloys at different compositions were measured and theoretically estimated using mixture rule for selected photon energy. Later on, total <span class="hlt">atomic</span> and electronic cross-sections and effective <span class="hlt">atomic</span> number for alloys are determined experimentally and theoretically using these mass attenuation coefficients. When these parameters are examined depending on the alloy compositions, thereof have been found to vary with the alloy composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhB.119..435K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhB.119..435K"><span id="translatedtitle">Production of <span class="hlt">warm</span> aluminum cluster anions by femtosecond laser ablation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kobayashi, T.; Matsuo, Y.</p> <p>2015-06-01</p> <p>We report on the production of <span class="hlt">warm</span> aluminum cluster anions, Al{/n -} (1 ≤ n ≤ 26), after femtosecond laser ablation of an aluminum nitride substrate. Large cluster anions of n ≥ 8 suffer metastable dissociation after their production, which indicates the internal energy of the cluster anions is high enough for the dissociation of an Al <span class="hlt">atom</span>. We find that the efficiency of metastable dissociation is dependent on the size of cluster anions and the dependence can be rationalized by the dissociation energy of an Al <span class="hlt">atom</span> from the cluster anions calculated with thermochemical data of the clusters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NatCC...4..143Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NatCC...4..143Z"><span id="translatedtitle">How <span class="hlt">warm</span> days increase belief in global <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaval, Lisa; Keenan, Elizabeth A.; Johnson, Eric J.; Weber, Elke U.</p> <p>2014-02-01</p> <p>Climate change judgements can depend on whether today seems warmer or colder than usual, termed the local <span class="hlt">warming</span> effect. Although previous research has demonstrated that this effect occurs, studies have yet to explain why or how temperature abnormalities influence global <span class="hlt">warming</span> attitudes. A better understanding of the underlying psychology of this effect can help explain the public's reaction to climate change and inform approaches used to communicate the phenomenon. Across five studies, we find evidence of attribute substitution, whereby individuals use less relevant but available information (for example, today's temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) when making judgements. Moreover, we rule out alternative hypotheses involving climate change labelling and lay mental models. Ultimately, we show that present temperature abnormalities are given undue weight and lead to an overestimation of the frequency of similar past events, thereby increasing belief in and concern for global <span class="hlt">warming</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=JOPERD&id=EJ925234','ERIC'); return false;" href="http://eric.ed.gov/?q=JOPERD&id=EJ925234"><span id="translatedtitle">Active Movement <span class="hlt">Warm</span>-Up Routines</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Walter, Teri; Quint, Ashleigh; Fischer, Kim; Kiger, Joy</p> <p>2011-01-01</p> <p>This article presents <span class="hlt">warm</span>-ups that are designed to physiologically and psychologically prepare students for vigorous physical activity. An active movement <span class="hlt">warm</span>-up routine is made up of three parts: (1) active <span class="hlt">warm</span>-up movement exercises, (2) general preparation, and (3) the energy system. These <span class="hlt">warm</span>-up routines can be used with all grade levels…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740010901','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740010901"><span id="translatedtitle">Analysis of data from spacecraft (stratospheric <span class="hlt">warmings</span>)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, A. D.</p> <p>1974-01-01</p> <p>Links between the upper atmosphere and the stratosphere were studied to explain stratospheric <span class="hlt">warmings</span>, and to correlate the <span class="hlt">warmings</span> with other terrestrial and solar phenomena. Physical mechanisms for <span class="hlt">warming</span>, or which may act as a trigger are discussed along with solar and geophysical indices. Two stratospheric <span class="hlt">warming</span> cases are analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......117A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......117A"><span id="translatedtitle">Experiments in cold <span class="hlt">atom</span> optics towards precision <span class="hlt">atom</span> interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aveline, David C.</p> <p></p> <p><span class="hlt">Atom</span> optics has been a highly active field of research with many scientific breakthroughs over the past two decades, largely due to successful advances in laser technology, microfabrication techniques, and the development of laser cooling and trapping of neutral <span class="hlt">atoms</span>. This dissertation details several <span class="hlt">atom</span> optics experiments with the motivation to develop tools and techniques for precision <span class="hlt">atom</span> wave interferometry. It provides background information about <span class="hlt">atom</span> optics and the fundamentals behind laser cooling and trapping, including basic techniques for cold gas thermometry and absorptive detection of <span class="hlt">atoms</span>. A brief overview of <span class="hlt">magnetic</span> trapping and guiding in tight wire-based traps is also provided before the experimental details are presented. We developed a novel laser source of 780 nm light using frequency-doubled 1560 nm fiber amplifier. This laser system provided up to a Watt of tunable frequency stabilized light for two Rb laser cooling and trapping experiments. One system generates Bose-Einstein condensates in an optical trap while the second is based on <span class="hlt">atom</span> chip <span class="hlt">magnetic</span> traps. The <span class="hlt">atom</span> chip system, detailed in this thesis, was designed and built to develop the tools necessary for transport and loading large numbers of cold <span class="hlt">atoms</span> and explore the potential for guided <span class="hlt">atom</span> interferometry. Techniques and results from this experiment are presented, including an efficient <span class="hlt">magnetic</span> transport and loading method to deliver cold <span class="hlt">atom</span> to <span class="hlt">atom</span> chip traps. We also developed a modeling tool for the <span class="hlt">magnetic</span> fields formed by coiled wire geometries, as well as planar wire patterns. These models helped us design traps and determine adiabatic transportation of cold <span class="hlt">atoms</span> between macro-scale traps and micro-traps formed on <span class="hlt">atom</span> chips. Having achieved near unity transfer efficiency, we demonstrated that this approach promises to be a consistent method for loading large numbers of <span class="hlt">atoms</span> into micro-traps. Furthermore, we discuss an in situ imaging technique to investigate <span class="hlt">magnetic</span> field contours of the traps and the dynamics of <span class="hlt">atoms</span> within those confining potentials. We also controlled the propagation along the <span class="hlt">atom</span> chip guides by accelerating <span class="hlt">atoms</span> with longitudinal <span class="hlt">magnetic</span> gradients, and investigated an <span class="hlt">atom</span> focusing scheme. While the <span class="hlt">atom</span> chip wire guides perform a role analogous to optical fibers guiding light waves, "free space" cold <span class="hlt">atoms</span> offer great opportunity for precision interferometry. We describe a second on-going <span class="hlt">atom</span> optics experiment that measures gravity gradients using a pair of <span class="hlt">atom</span> fountain interferometers separated by one meter. We have demonstrated Gravity Gradiometer resolution down to 4x10-9 g/m using a 40 kg test mass. The <span class="hlt">atomic</span> physics subsystem is described in detail, including the vacuum, cold <span class="hlt">atom</span> source, optics, <span class="hlt">magnetic</span> coils and shields, and vibration isolation and compensation. The system is designed to be a compact, robust, transportable instrument, taking strides towards future gravity gradient measurements in the field. In the realm of space applications, there has been interest for micro-gravity science experiments aboard the International Space Station, along with instrument development for gravity mapping of Earth and planetary bodies with satellite-based instruments. Furthermore, there are ground-based applications for gravity imaging of local density distributions, precision measurement of gravity, as well as proposals for redefining the kilogram, detecting gravitational waves and determining the Gravitational constant.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LNP...911..111E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LNP...911..111E"><span id="translatedtitle">Cold <span class="hlt">Atom</span> Magnetometers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eto, Yujiro; Sadrove, Mark; Hirano, Takuya</p> <p></p> <p>Detection of weak <span class="hlt">magnetic</span> fields with high spatial resolution is an important technology for various applications such as biological imaging, detection of MRI signals and fundamental physics. Cold <span class="hlt">atom</span> magnetometry enables 10-11 T/ <math xmlns:xlink="http://www.w3.org/1999/xlink"> <msqrt> <mrow> <mtext>Hz</mtext> </mrow> </msqrt> sqrt{text{Hz}} sensitivities at the micron scale, that is, at the scale of a typical biological cell size. This magnetometry takes advantage of unique properties of <span class="hlt">atomic</span> gaseous Bose-Einstein condensates with internal spin degrees of freedom. In this chapter, we first overview various state-of-the-art magnetometers, addressing their sensitivities and spatial resolutions. Then we describe properties of spinor condensates, ultracold <span class="hlt">atom</span> magnetometers, and the latest research developments achieved in the FIRST project, especially for the detection of alternate current <span class="hlt">magnetic</span> fields using a spin-echo-based magnetometer. We also discuss future prospects of the magnetometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26252684','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26252684"><span id="translatedtitle"><span class="hlt">Atom</span>-Light Hybrid Interferometer.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L Q; Ou, Z Y; Zhang, Weiping</p> <p>2015-07-24</p> <p>A new type of hybrid <span class="hlt">atom</span>-light interferometer is demonstrated with <span class="hlt">atomic</span> Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and <span class="hlt">atomic</span> waves in the two arms. The correlation between <span class="hlt">atoms</span> and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the <span class="hlt">atomic</span> phase via a <span class="hlt">magnetic</span> field change. This new <span class="hlt">atom</span>-light correlated hybrid interferometer is a sensitive probe of the <span class="hlt">atomic</span> internal state and should find wide applications in precision measurement and quantum control with <span class="hlt">atoms</span> and photons. PMID:26252684</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16216650','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16216650"><span id="translatedtitle">Global <span class="hlt">warming</span> and infectious disease.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Khasnis, Atul A; Nettleman, Mary D</p> <p>2005-01-01</p> <p>Global <span class="hlt">warming</span> has serious implications for all aspects of human life, including infectious diseases. The effect of global <span class="hlt">warming</span> depends on the complex interaction between the human host population and the causative infectious agent. From the human standpoint, changes in the environment may trigger human migration, causing disease patterns to shift. Crop failures and famine may reduce host resistance to infections. Disease transmission may be enhanced through the scarcity and contamination of potable water sources. Importantly, significant economic and political stresses may damage the existing public health infrastructure, leaving mankind poorly prepared for unexpected epidemics. Global <span class="hlt">warming</span> will certainly affect the abundance and distribution of disease vectors. Altitudes that are currently too cool to sustain vectors will become more conducive to them. Some vector populations may expand into new geographic areas, whereas others may disappear. Malaria, dengue, plague, and viruses causing encephalitic syndromes are among the many vector-borne diseases likely to be affected. Some models suggest that vector-borne diseases will become more common as the earth <span class="hlt">warms</span>, although caution is needed in interpreting these predictions. Clearly, global <span class="hlt">warming</span> will cause changes in the epidemiology of infectious diseases. The ability of mankind to react or adapt is dependent upon the magnitude and speed of the change. The outcome will also depend on our ability to recognize epidemics early, to contain them effectively, to provide appropriate treatment, and to commit resources to prevention and research. PMID:16216650</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/530884','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/530884"><span id="translatedtitle"><span class="hlt">Warming</span> early Earth and Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kasting, J.F.</p> <p>1997-05-23</p> <p>Sagan and Chyba, in their article on page 1217 of this issue, have revived an old debate about how liquid water was maintained on early Earth and Mars despite a solar luminosity 25 to 30% lower than that at present. A theory that has been popular for some time is that greatly elevated concentrations of atmospheric COD produced by the action of the carbonate-silicate cycle, provided enough of a greenhouse effect to <span class="hlt">warm</span> early Earth. However, Rye et al. have placed geochemical constraints on early atmospheric CO{sub 2} abundances that fall well below the levels needed to <span class="hlt">warm</span> the surface. These constraints are based on the absence of siderite (FeCO{sub 3}) in ancient soil profiles-a negative and, hence, rather weak form of evidence- and apply to the time period 2.2 to 2.8 billion years ago, when Earth was already middle aged. Nonetheless, the soil data provide some indication that atmospheric CO{sub 2} levels may have been lower than previously thought. An even more serious problem arises if one tries to keep early Mars <span class="hlt">warm</span> with CO{sub 2}. Model calculations predict that CO{sub 2} clouds would form on Mars in the upper troposphere, reducing the lapse rate and severely limiting the amount of surface <span class="hlt">warming</span>. A suggestion that CO{sub 2} clouds may have <span class="hlt">warmed</span> the planet radiatively has yet to be borne out by detailed calculations. 26 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MAR.K1261H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MAR.K1261H"><span id="translatedtitle"><span class="hlt">Atoms</span> talking to SQUIDs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoffman, J. E.; Grover, J. A.; Ravets, S.; Voigt, K. D.; Lee, J.; Kim, Z.; Wood, A. K.; Schoch, I.; Anderson, J. R.; Dragt, A. J.; Hafezi, M.; Lobb, C. J.; Orozco, L. A.; Rolston, S. L.; Taylor, J. M.; Wellstood, F. C.</p> <p>2012-02-01</p> <p>We present our advances towards a hybrid quantum system of ^87Rb <span class="hlt">atoms</span> coupled to a superconducting flux qubit through the <span class="hlt">magnetic</span> dipole transition. We plan to trap <span class="hlt">atoms</span> in the evanescent field outside a 500 nm nanofiber. This will allow us to bring the <span class="hlt">atoms</span> less than 5 μm above the surface of the superconductor without producing excessive heating or changing <span class="hlt">magnetic</span> fields. As an intermediate step, we plan on coupling the <span class="hlt">atoms</span> to a superconducting LC resonator. Current progress includes production of nanofibers with >98% transmission, and a tunable high-Q superconducting resonator. Additionally, we show how to use our system as a unified interface for microwave and optical photons, in which the <span class="hlt">atoms</span> act both as a quantum memory and transduce excitations between the two frequency domains. Using coherent control techniques, we examine conversion and storage of quantum information between microwave photons in superconducting resonators, ensembles of ultracold <span class="hlt">atoms</span>, and optical photons as well as a method for transferring information between two resonators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25865795','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25865795"><span id="translatedtitle">Selenium speciation using capillary electrophoresis coupled with modified electrothermal <span class="hlt">atomic</span> absorption spectrometry after selective extraction with 5-sulfosalicylic acid functionalized <span class="hlt">magnetic</span> nanoparticles.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Lizhen; Deng, Biyang; Shen, Caiying; Long, Chanjuan; Deng, Qiufen; Tao, Chunyao</p> <p>2015-05-22</p> <p>A new method for selenium speciation in fermented bean curd wastewater and juice was described. This method involved sample extraction with 5-sulfosalicylic acid (SSA)-functionalized silica-coated <span class="hlt">magnetic</span> nanoparticles (SMNPs), capillary electrophoresis (CE) separation, and online detection with a modified electrothermal <span class="hlt">atomic</span> absorption spectrometry (ETAAS) system. The modified interface for ETAAS allowed for the introduction of CE effluent directly through the end of the graphite tube. Elimination of the upper injection hole of the graphite tube reduced the loss of the anlayte and enhanced the detection sensitivity. The SSA-SMNPs were synthesized and used to extract trace amounts of selenite [Se(IV)], selenite [Se(VI)], selenomethionine (SeMet), and selenocystine (SeCys2) from dilute samples. The concentration enrichment factors for Se(VI), Se(IV), SeMet, and SeCys2 were 21, 29, 18, and 12, respectively, using the SSA-SMNPs extraction. The limits of detection for Se(VI), Se(IV), SeMet, and SeCys2 were 0.18, 0.17, 0.54, 0.49ngmL(-1), respectively. The RSD values (n=6) of method for intraday were observed between 0.7% and 2.9%. The RSD values of method for interday were less than 3.5%. The linear range of Se(VI) and Se(IV) were in the range of 0.5-200ngmL(-1), and the linear ranges of SeMet and SeCys2 were 2-500 and 2-1000ngmL(-1), respectively. The detection limits of this method were improved by 10 times due to the enrichment by the SSA-SMNP extraction. The contents of Se(VI) and Se(IV) in fermented bean curd wastewater were measured as 3.83 and 2.62ngmL(-1), respectively. The contents of Se(VI), Se(IV), SeMet, and SeCys2 in fermented bean curd juice were determined as 6.39, 4.08, 2.77, and 4.00ngmL(-1), respectively. The recoveries were in the range of 99.14-104.5% and the RSDs (n=6) of recoveries between 0.82% and 3.5%. PMID:25865795</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21052870','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21052870"><span id="translatedtitle">Cosmic Rays and Global <span class="hlt">Warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sloan, T.; Wolfendale, A. W.</p> <p>2008-01-24</p> <p>Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, are causal. The possibility arises, therefore, of a connection between cosmic rays and Global <span class="hlt">Warming</span>. If true, the implications would be very great. We have examined this claim in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle <span class="hlt">warming</span> variations are due to cosmic rays and less than 2% of the <span class="hlt">warming</span> over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1195936','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1195936"><span id="translatedtitle">High data rate <span class="hlt">atom</span> interferometric device</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash</p> <p>2015-07-21</p> <p>A light-pulse <span class="hlt">atomic</span> interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of <span class="hlt">magnetic</span> coils configured to <span class="hlt">magnetically</span> confine an <span class="hlt">atomic</span> vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the <span class="hlt">atomic</span> vapor within the vessel with laser radiation that, when suitably tuned, can launch <span class="hlt">atoms</span> previously confined in each of the MOTs toward the other MOT. In embodiments, the <span class="hlt">magnetic</span> coils are configured to produce a <span class="hlt">magnetic</span> field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched <span class="hlt">atoms</span> from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the <span class="hlt">magnetic</span> coils according to a particular temporal <span class="hlt">magnetic</span> field gradient profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMGP32B..07D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMGP32B..07D"><span id="translatedtitle">Partial Transition <span class="hlt">Warming</span> Remanence ("Inverse TRM")</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunlop, D. J.</p> <p>2001-12-01</p> <p>"Inverse TRM" (ITRM) produced by <span class="hlt">warming</span> magnetite through the Verwey transition was discovered by Nagata et al. (1963), who speculated that the NRM of magnetite-bearing meteorites could be in part ITRM acquired by <span class="hlt">warming</span> in the Earth's <span class="hlt">magnetic</span> field after impact rather than a record of extraterrestrial fields. New results are reported here for ITRM and partial ITRM (acquired over narrow intervals of temperature during <span class="hlt">warming</span>), including tests of partial ITRM additivity and reciprocity intended to lay the groundwork for an ITRM Thellier-analog cooling method of paleointensity determination. Memory ratios for ITRM low-temperature demagnetization (LTD) ranged from 0.254 to 0.092 for 0.6-135 um magnetites. ITRM was less resistant to LTD than TRM, leaving an ITRM memory similar to remanence after 15 mT AF cleaning. However, ITRM memory was much more stable against thermal demagnetization than the original ITRM and would contaminate NRM up to the highest steps of paleointensity determination. Next the thermal demagnetization of total ITRM and of a partial ITRM produced by switching off the field partway through <span class="hlt">warming</span> from 77 K to 300 K were compared for nine magnetite size fractions. For the 1-14 um magnetites, 75-85% of the ITRM decayed quasi-linearly from 25 to 550oC, then dropped to zero by 570oC. The 20, 110 and 135 um magnetites demagnetized in two stages: a 50% loss from 20-250oC, a leveling out until 500oC, and a final plunge to zero above 550oC. Partial ITRMs of 0.6-20 um magnetites were more resistant to thermal demagnetization than total ITRMs. The decay was still quasi-linear or two-stage, but twice as much remanence survived at 550oC. The most stable part of ITRM seems to be acquired in the earliest stages of the Verwey transition, well below 120 K. The final experiments studied sets of neighbouring partial ITRMs, using 12 narrow T intervals from 20 to 300 K. The reciprocity law was obeyed for all samples: pITRM(T1, T2) was completely erased by zero-field cooling from T2 to T1. This is the main requirement for a successful paleointensity method. The largest pITRMs were acquired in the 90-100 and 100-110 K intervals, not between 110 and 120 K. This is surprising because most of the LTD of total ITRM and other remanences occurs from 120-110 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007DPS....39.3403S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007DPS....39.3403S"><span id="translatedtitle">The Spitzer <span class="hlt">Warm</span> Mission: Hot Science with a "<span class="hlt">Warm</span>" Telescope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Squires, Gordon K.; Helou, G.; Soifer, T.; Carey, S.; Rebull, L.; Stauffer, J. R.; Storrie-Lombardi, L. J.; Warm Mission white papers, Spitzer</p> <p>2007-10-01</p> <p>The Spitzer Space Telescope is the infrared component of NASA's family of Great Observatories comprised of the Chandra X-ray Observatory, the Compton Gamma Ray Observatory, and the Hubble Space Telescope. Cryogenically cooled and in Earth-trailing orbit, Spitzer currently offers imaging capabilities from 3.6-160 microns, and spectroscopy from 5-38 microns. In approximately March 2009, the liquid helium cryogen on-board Spitzer will be expended, but the observatory will remain operative with 3.6 and 4.5 micron imaging capabilities over two 5'x5’ fields-of-view. Sensitivity in these channels will remain unchanged from the cryogenic mission. In this "warm” mission phase, Spitzer can operate until early 2014 with high-efficiency, providing up to 35,000 hours of science observing time. This enables several unprecedented opportunities to address fundamental and key scientific questions requiring large allocations of observing time, while maintaining opportunities for broad community use with more "traditional” time allocations. This poster summarizes some of the possible large scientific programs enabled by a Spitzer <span class="hlt">warm</span> mission, including support for theory and archival programs. The content is summarized from contributed white papers to the Spitzer <span class="hlt">Warm</span> Mission workshop, held in Pasadena, CA in June 2007. For detailed information on these and other science programs possible with <span class="hlt">warm</span> Spitzer observations, please see: http://ssc.spitzer.caltech.edu/mtgs/<span class="hlt">warm</span>/</u></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/10141155','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/10141155"><span id="translatedtitle">Global <span class="hlt">Warming</span>: Physics and Facts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Levi, B.G.; Hafemeister, D.; Scribner, R.</p> <p>1992-05-01</p> <p>This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth`s radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global <span class="hlt">warming</span>; the physical and policy linkages; policy implications of greenhouse <span class="hlt">warming</span>; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5392426','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5392426"><span id="translatedtitle">Global <span class="hlt">Warming</span>: Physics and Facts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Levi, B.G. ); Hafemeister, D. , Washington, DC ); Scribner, R. )</p> <p>1992-01-01</p> <p>This report contains papers on: A tutorial on global atmospheric energetics and the greenhouse effect; global climate models: what and how; comparison of general circulation models; climate and the earth's radiation budget; temperature and sea level change; short-term climate variability and predictions; the great ocean conveyor; trace gases in the atmosphere: temporal and spatial trends; the geochemical carbon cycle and the uptake of fossil fuel CO{sub 2}; forestry and global <span class="hlt">warming</span>; the physical and policy linkages; policy implications of greenhouse <span class="hlt">warming</span>; options for lowering US carbon dioxide emissions; options for reducing carbon dioxide emissions; and science and diplomacy: a new partnership to protect the environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000EOSTr..81Q.266S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000EOSTr..81Q.266S"><span id="translatedtitle">Global <span class="hlt">warming</span> at the summit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Showstack, Randy</p> <p></p> <p>During the recent summit meeting between Russian President Vladimir Putin and U.S. President Bill Clinton, the two leaders reaffirmed their concerns about global <span class="hlt">warming</span> and the need to continue to take actions to try to reduce the threat.In a June 4 joint statement, they stressed the need to develop flexibility mechanisms, including international emissions trading, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. They also noted that initiatives to reduce the risk of greenhouse <span class="hlt">warming</span>, including specific mechanisms of the Kyoto Protocol, could potentially promote economic growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920006216','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920006216"><span id="translatedtitle">Halocarbon ozone depletion and global <span class="hlt">warming</span> potentials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cox, Richard A.; Wuebbles, D.; Atkinson, R.; Connell, Peter S.; Dorn, H. P.; Derudder, A.; Derwent, Richard G.; Fehsenfeld, F. C.; Fisher, D.; Isaksen, Ivar S. A.</p> <p>1990-01-01</p> <p>Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H <span class="hlt">atom</span>, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen <span class="hlt">atom</span> in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global <span class="hlt">warming</span>).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JChPh.129v4103H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JChPh.129v4103H"><span id="translatedtitle">Relativistic calculation of nuclear <span class="hlt">magnetic</span> shielding tensor using the regular approximation to the normalized elimination of the small component. III. Introduction of gauge-including <span class="hlt">atomic</span> orbitals and a finite-size nuclear model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamaya, S.; Maeda, H.; Funaki, M.; Fukui, H.</p> <p>2008-12-01</p> <p>The relativistic calculation of nuclear <span class="hlt">magnetic</span> shielding tensors in hydrogen halides is performed using the second-order regular approximation to the normalized elimination of the small component (SORA-NESC) method with the inclusion of the perturbation terms from the metric operator. This computational scheme is denoted as SORA-Met. The SORA-Met calculation yields anisotropies, Δσ =σ∥-σ⊥, for the halogen nuclei in hydrogen halides that are too small. In the NESC theory, the small component of the spinor is combined to the large component via the operator σ⃗ṡπ⃗U/2c, in which π⃗=p⃗+A⃗, U is a nonunitary transformation operator, and c ≅137.036 a.u. is the velocity of light. The operator U depends on the vector potential A⃗ (i.e., the <span class="hlt">magnetic</span> perturbations in the system) with the leading order c-2 and the <span class="hlt">magnetic</span> perturbation terms of U contribute to the Hamiltonian and metric operators of the system in the leading order c-4. It is shown that the small Δσ for halogen nuclei found in our previous studies is related to the neglect of the U(0,1) perturbation operator of U, which is independent of the external <span class="hlt">magnetic</span> field and of the first order with respect to the nuclear <span class="hlt">magnetic</span> dipole moment. Introduction of gauge-including <span class="hlt">atomic</span> orbitals and a finite-size nuclear model is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22390940','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22390940"><span id="translatedtitle"><span class="hlt">Atomic</span> polarizabilities</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.</p> <p>2015-01-22</p> <p>The <span class="hlt">atomic</span> dipole polarizability governs the first-order response of an <span class="hlt">atom</span> to an applied electric field. <span class="hlt">Atomic</span> polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of <span class="hlt">atomic</span> polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent <span class="hlt">atoms</span> is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5495825','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5495825"><span id="translatedtitle">Policy implications of greenhouse <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1991-01-01</p> <p>Contents: background; the greenhouse gases and their effects; policy framework; adaptation; mitigation; international considerations; findings and conclusions; recommendations; questions and answers about greenhouse <span class="hlt">warming</span>; background information on synthesis panel members and professional staff; and membership lists for effects, mitigation, and adaptation panels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20898643','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20898643"><span id="translatedtitle">Coherent <span class="hlt">Atom</span> Optics with fast metastable rare gas <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Vassilev, G.; Ducloy, M.; Bocvarski, V.</p> <p>2006-12-01</p> <p>Coherent <span class="hlt">atom</span> optics experiments making use of an ultra-narrow beam of fast metastable <span class="hlt">atoms</span> generated by metastability exchange are reported. The transverse coherence of the beam (coherence radius of 1.7 {mu}m for He*, 1.2 {mu}m for Ne*, 0.87 {mu}m for Ar*) is demonstrated via the <span class="hlt">atomic</span> diffraction by a non-<span class="hlt">magnetic</span> 2{mu}m-period reflection grating. The combination of the non-scalar van der Waals (vdW) interaction with the Zeeman interaction generated by a static <span class="hlt">magnetic</span> field gives rise to ''vdW-Zeeman'' transitions among Zeeman sub-levels. Exo-energetic transitions of this type are observed with Ne*(3P2) <span class="hlt">atoms</span> traversing a copper micro-slit grating. They can be used as a tunable beam splitter in an inelastic Fresnel bi-prism <span class="hlt">atom</span> interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AIPC..876...28G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AIPC..876...28G"><span id="translatedtitle">Coherent <span class="hlt">Atom</span> Optics with fast metastable rare gas <span class="hlt">atoms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Bocvarski, V.; Vassilev, G.; Ducloy, M.</p> <p>2006-12-01</p> <p>Coherent <span class="hlt">atom</span> optics experiments making use of an ultra-narrow beam of fast metastable <span class="hlt">atoms</span> generated by metastability exchange are reported. The transverse coherence of the beam (coherence radius of 1.7 μm for He*, 1.2 μm for Ne*, 0.87 μm for Ar*) is demonstrated via the <span class="hlt">atomic</span> diffraction by a non-<span class="hlt">magnetic</span> 2μm-period reflection grating. The combination of the non-scalar van der Waals (vdW) interaction with the Zeeman interaction generated by a static <span class="hlt">magnetic</span> field gives rise to "vdW-Zeeman" transitions among Zeeman sub-levels. Exo-energetic transitions of this type are observed with Ne*(3P2) <span class="hlt">atoms</span> traversing a copper micro-slit grating. They can be used as a tunable beam splitter in an inelastic Fresnel bi-prism <span class="hlt">atom</span> interferometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NatCC...2..530K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NatCC...2..530K"><span id="translatedtitle">Equatorial refuge amid tropical <span class="hlt">warming</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karnauskas, Kristopher B.; Cohen, Anne L.</p> <p>2012-07-01</p> <p>Upwelling across the tropical Pacific Ocean is projected to weaken in accordance with a reduction of the atmospheric overturning circulation, enhancing the increase in sea surface temperature relative to other regions in response to greenhouse-gas forcing. In the central Pacific, home to one of the largest marine protected areas and fishery regions in the global tropics, sea surface temperatures are projected to increase by 2.8C by the end of this century. Of critical concern is that marine protected areas may not provide refuge from the anticipated rate of large-scale <span class="hlt">warming</span>, which could exceed the evolutionary capacity of coral and their symbionts to adapt. Combining high-resolution satellite measurements, an ensemble of global climate models and an eddy-resolving regional ocean circulation model, we show that <span class="hlt">warming</span> and productivity decline around select Pacific islands will be mitigated by enhanced upwelling associated with a strengthening of the equatorial undercurrent. Enhanced topographic upwelling will act as a negative feedback, locally mitigating the surface <span class="hlt">warming</span>. At the Gilbert Islands, the rate of <span class="hlt">warming</span> will be reduced by 0.7+/-0.3C or 25+/-9% per century, or an overall cooling effect comparable to the local anomaly for a typical El Nio, by the end of this century. As the equatorial undercurrent is dynamically constrained to the Equator, only a handful of coral reefs stand to benefit from this equatorial island effect. Nevertheless, those that do face a lower rate of <span class="hlt">warming</span>, conferring a significant advantage over neighbouring reef systems. If realized, these predictions help to identify potential refuges for coral reef communities from anticipated climate changes of the twenty-first century.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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