in the a-b plane at 295, 200, and 15 K, using the model for a lamellar plate. Several overdamped Lorentzian, the reflectance and optical conductivity have also been fitted using a factorized form of the dielectric function to the removal of degeneracy of this mode. ACKNOWLEDGMENTS We are grateful to A. R. Moodenbaugh for performing

An exploratory program was conducted to design and develop free standing a-b plane pyrolytic graphite throat inserts for rocket nozzles. Thermal analysis and structural analysis were conducted to define and establish design concepts for nozzle inserts. Fr...

Optical reflection measurements within the highly conducting (a,b) plane of the organic metal (BEDT-TTF)4[Ni(dto)2] reveal the gradual development of a sharp feature at around 200 cm-1 as the temperature is reduced below 150 K. Below this frequency a narrow Drude-like response is observed which accounts for the metallic behavior. Since de Haas-van Alphen ...

Electrons and phonons are the carriers of heat in the a-b plane of the high-T[sub c] superconductor YBa[sub 2]Cu[sub 3]O[sub 7]. In the absence of boundary scattering, the a-b plane thermal conductivity and the mean free path of each carrier type are calculated as functions of temperature using kinetic theory, the two-fluid model of the superconducting state, and experimental ...

Large (mm-sized) crystals of the single-layer high-Tc superconductor HgBa_2CuO_4+? (Hg1201) have been grown via a new technique using a flux-based method; the optimally-doped samples have sharply-defined transitions at T_c? 96 K. The reflectance has been measured above and below Tc over a wide frequency range for light polarized parallel and perpendicular to the copper-oxygen planes. The ...

The peak dimensionless thermoelectric figure-of-merit (ZT) of Bi(2)Te(3)-based n-type single crystals is about 0.85 in the ab plane at room temperature, which has not been improved over the last 50 years due to the high thermal conductivity of 1.65 W m(-1) K(-1) even though the power factor is 47 x 10(-4) W m(-1) K(-2). In samples with ...

We report on the anisotropic response, the charge and lattice dynamics of normal and charge ordered phases with horizontal stripes in single crystals of the organic conductor ?-(BEDT-TTF)2I3 determined by dc resistivity and dielectric and optical spectroscopy. An overdamped Drude response and a small conductivity anisotropy observed in ...

The ab-plane optical reflectance of single crystal of Bi2Sr2Ca(Cu1- xNix)2O8+?, for x=0.0215, has been measured from 80 to 40000 cm-1 (10 meV-5 eV) and at temperatures between 20 and 300 K. Through Ni substitution, the optical conductivity shows a broad peak at about 400 cm-1, which grows in intensity and shifts to lower frequency as ...

Polycrystalline samples of Nd1-xCaxBa2-xLaxCu3O7-? (with 0.0 ? x ? 0.15) were prepared by the standard solid state method. The co-doping effect was studied on the resistivity as a function of temperature and doping concentration x. The fluctuation conductivity was analyzed using the Aslamazov and Larkin model (AL). For all samples, three fluctuation regions; i.e. ...

We have measured the resistive transitions of c-axis oriented YBCO thin films in applied magnetic fields for both H ab planes and H c axis up to 8T. We have analyzed the data using the 3D fluctuation theory of Ullah and Dorsey, and found a good fit to the predicted scaling function above and below the onset of the transition. The deduced Tc(H) is linear ...

The family of two-dimensional magnetic materials M(II)PS(3) where M = Mn, Fe, Ni, Mg, Zn, etc shows a wide range of fascinating magnetic behaviour. It also shows potentially useful chemical properties including intercalation of nonlinear optical molecules and lithium ions. These properties are due to a crystal structure in which the ab ...

Field angle dependent critical current, magneto-optical microscopy and high resolution electron microscopy studies have been performed on YBa2Cu3O7-? thin films grown on miscut substrates. High resolution electron microscopy images show that the films studied exhibited clean epitaxial growth with a low density of antiphase boundaries and stacking faults. Any antiphase ...

The infrared properties of the newly discovered high temperature super-conductors are extremely unusual. We have extensively studied two cuprate families: rm La_{2-it x}Sr_{ it x}CuO_4 and rm YBa_2Cu_3O_{7-delta}. The former is the material where high T _{c} was first discovered; the latter is the first substance with a transition temperature above the liquid nitrogen boiling point. The samples ...

High Li+ conductivity in the high-temperature (hexagonal) phase of LiBH4 is revealed through a first-principles molecular dynamics simulation of 1200 atoms using periodic boundary conditions. The high ionic conductivity originates from the generation of a Li+ metastable state located at an interstitial site surrounded by three Li+ ions and three BH4- ions ...

Theoretical results for the ab -plane tunneling conductance in the d -wave model for high-T{sub c} superconductors are presented. The d -wave model predicts surface bound states below the maximum gap. A subdominant order parameter, stabilized by the surface, leads to a splitting of the zero-bias conductance peak ...

... runs wre made to produce the throat inserts. ... Descriptors : *NOZZLE THROATS, *PYROLYTIC GRAPHITE, *NOZZLE INSERTS, STRESS ANALYSIS ...

High quality single crystals of incongruently melting SrCu2(BO3)2, both pure and doped with Mg, La and Na have been grown by optical floating zone (OFZ)-image furnace technique using self-flux. The obtained single crystals were characterized by X-ray powder diffraction and by neutron scattering using highly enriched 11B for selected crystals. Magnetic susceptibility ...

The layered structure of the cuprate superconductors leads to a significant anisotropy between ab-plane and c-axis properties which is significantly greater in Bi_2Sr_2CaCu_2O_8 (BSCCO) than in rm YBa_2Cu_3 O_{7-x} (YBCO); likely due to differences in intercalary structure since both systems contain double CuO_2 layers. rm Pb_2Sr_2(Y/Ca)Cu _3O_8 (PSYCCO) is another system ...

Post-sintering treatments such as zone melting under thermal gradient has been conducted on sintered YBCO tape cast films. YBCO precursor powder was derived through decomposition of a mixture of nitrates of cations in a microwave oven for {approx}4 min. The resulting powder was characterized and made into thin sheets by tape casting and then sintered at 945 C for 5 h. The ...

We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC6. The tunneling conductance spectra, measured between 3 and 15 K, show a clear superconducting gap in the quasiparticle density of states. The gap function extracted from the spectra is in good agreement with the conventional BCS theory with Delta0=1.6+/-0.2 meV. The ...

Recently reported quasiparticle interference imaging in underdoped Ca(Fe1-xCox)2As2 shows pronounced C2 asymmetry, which is interpreted as an indication of an electronic nematic phase with a unidirectional electron band, dispersive predominantly along the b axis of this orthorhombic material. On the other hand, even more recent transport measurements on untwinned samples show near isotropy of the ...

The tunneling conductance G(V,T) of (Pb film)-I-BI{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} junctions on cleaved ab planes typically reveals two gap features. The inner gap {Delta}{sub i} closes, in a BCS-like fashion, at a temperature T{sub ci} below the crystal {Tc} (90K). We can explain the inner gap behaviour {Delta}{sub i}(T), and ...

The use of solution techniques applied to the synthesis of superconducting oxides is discussed. Carbon containing precursors, nitrates, and hydroxides are compared, emphasizing coprecipitated hydroxides as reactive precursors for the synthesis of YBa2Cu3O7. A pure phase is observed at 750-800 C. But it remains tetragonal even after oxygen annealing at 500 C because of a microtwinning in the (a,c) ...

Planar tunneling spectroscopy is performed into the a-b plane of the high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. The tunneling spectra exhibit a zero-bias conductance peak (ZBCP). Preliminary studies as a function of temperature, crystallographic orientation, magnetic field magnitude and direction confirm the ZBCP is an Andreev bound state (ABS) at ...

Single crystals untwinned optimally doped YBa{sub 2}Cu{sub 3}O{sub 9.65} show a large degree of anisotropy in a-b plane properties such as resistivity, infrared conductivity and value of zero temperature penetration depth. This source of orthorhombicity must ultimately reside in the CuO chains. Using a three plane model; 2 CuO{sub 2} and one CuO (chain plane), the authors ...

A new noncentrosymmetric ferroborate crystal, K2Fe2B2O7, has been grown from high temperature melt. Structure solution from single crystal X-ray diffraction shows that the title compound crystallizes in a trigonal space group P321 with cell dimensions of a=8.7475(12) � and c=8.5124(17) �. In the structure, FeO4 tetrahedron shares its three basal oxygen atoms with BO3 triangles forming a ...

We have studied thermal fluctuations of the electrical conductivity in melt-textured YBa2Cu3O7 (YBCO) samples under low magnetic fields. Measurements were performed either for current applied parallel or perpendicular to the c-axis and fluctuation conductivity was studied in the proximity of the superconducting transition. Two melt processed samples were ...

... with the polymer formed the ... Descriptors : *CONDUCTIVITY, *POLYMERS, *OPTICAL SWITCHING ... ELECTRON TRANSFER, SALTS, ABSORPTION ...

We have used a novel bolometric technique and a resonant technique to obtain accurate submillimeter and microwave residual loss data for epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8}. For all films we obtain good agreement between the submillimeter and microwave data, with the residual losses in both the ...

The (0 0 l) textured BaBi{sub 2}(Nb{sub 1-x}V{sub x}){sub 2}O{sub 9} (where x = 0, 0.03, 0.07, 0.1 and 0.13) ceramics were fabricated via the conventional melt-quenching technique followed by high temperature heat-treatment (800-1000 deg. C range). The influence of vanadium content and sintering temperature on the texture development and relative density were investigated. The samples ...

An approach to microwave measurements is used in order to determine both, the in-plane and out-of-plane conductivity of the high- Tc superconductor HgBa2CuO4+? near optimal doping. Unlike the ab -plane conductivity, the c -axis conductivity is highly sensitive to superconducting ...

In connection with two groups of experimental data, a calculation is performed of quantum interference corrections in a quasi-two-dimensional metal to conductivity as a function of temperature and magnetic field. For the temperature dependence a cross-over between a two-dimensional (2D) (higher temperatures) and 3D (lower temperatures) behavior is obtained. In the 3D limit the ...

In connection with two groups of experimental data, a calculation is performed of quantum interference corrections in a quasi-two-dimensional metal to conductivity as a function of temperature and magnetic field. For the temperature dependence a cross-over between a two-dimensional (2D) (higher temperatures) and 3D (lower temperatures) behavior is obtained. In the 3D limit the ...

The superconductor�barrier�superconductor interface in a range of YBa2Cu3O7 ? ? (YBCO) step-edge Josephson junctions was engineered to lie at angles ? other than normal to the a�b axes of the YBCO crystal. This systematic study enabled the effect of the d-wave anisotropy to be probed over the range ? = 0� ([100] direction) to ? = 45� ([110] direction) in a way not possible with junction ...

The Fermi surfaces of Fe-pnictide superconductors are fairly two-dimensional, and it has thus come as a surprise that recent penetration depth and thermal conductivity measurements on systems of the 122 type have reported c-axis transport coefficients at low temperatures in the superconducting state comparable to or even larger than that in the ab ...

The Fermi surfaces of Fe-pnictide superconductors are fairly two-dimensional (2D), and it has thus come as a surprise that recent penetration depth and thermal conductivity measurements on some systems have reported c-axis transport at low temperatures in the superconducting state comparable to or even larger than that in the ab plane. ...

Thermal conductivity, ?(T), electrical resistivity, ?(T), and magnetization, M(H), of the melt-textured Y123/Y211 (YBa2Cu3O7??/Y2BaCuO5) composites have been studied in the ab plane and along the c axis in normal and superconducting states. Detailed measurements of these quantities have been performed in the temperature range between 4 ...

The far-infrared transmission spectra for high-conductivity Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} films with the radiation polarized in the {ital ab} plane have been measured for temperatures above and below {ital T}{sub {ital c}}. The normal-state properties show a Drude-like response. The transmission spectrum can be used to derive ...

... 5. FUNDING NUMBERS Optically Switchable Conductive Polymers ... dI rIb',o t, ( TITLE: Optically Switchable Conductive Polymers ...

We present the results of an optical method of quantitatively estimating the spin exchange interactions in hexagonal manganites RMnO3 (R = Tb, Dy, Ho, Er) epitaxial thin films. The two in-plane (a-b plane) spin exchange integrals J1 (intratrimer Mn-Mn interaction) and J2 (intertrimer Mn-Mn interaction) are deduced from the magnon scattering peak wavenumbers. We found that J2 ...

We measured the phonon dispersions of YBa{sub 2}Cu{sub 3}O{sub 6.15} and YBa{sub 2}Cu{sub 3}O{sub 6.95} by time-of-flight inelastic neutron scattering. The in-plane bond-stretching modes in the metallic phase showed a distinct a-b plane anisotropy beyond what is expected for structural origin. Such anisotropy in the longitudinal optical modes, which is absent in the TO, ...

Studies of YBa{sub 2}Cu{sub 3}O{sub 7} films on Li{sub 2}B{sub 4}O{sub 7} substrates showed that the excitation energy of plasmons related to free carriers is weakly anisotropic in the ab plane. The corresponding splitting (0.16 eV) is far less than that in crystals ({approx_equal}0.58 eV). The splitting of plasmons related to the valence electrons lies ...

In ZnO hierarchical heterostructures of zinc antimonate nanoislands on ZnO nanobelts, the substitution of Sb(5+) for Zn(2+) induces lattice contraction and a variation in vacancy defects, and moreover the preferential accumulation and segregation of Sb in [001] planes results in the intense perturbation of atomic motion in the a-b plane. Under nonresonant conditions, nonpolar E(2)(high) and polar ...

We report resistivity, magnetization, critical current density, and the upper critical field of the single crystalline FeTe0.61Se0.39 with Tc � 14 K synthesized via slow-furnace cooling followed by low-temperature annealing. Magneto-optical observation confirms the uniformity of current flow in the crystal and the critical current density is estimated to exceed 1 � 105 ...

In this thesis, results of the investigation of a new low-dimensional cobaltates Ba2-xSrxCoO 4 are presented. The synthesis of both polycrystalline and single crystalline compounds using the methods of conventional solid state chemical reaction and floating-zone optical furnace is first introduced. Besides making polycrystalline powders, we successfully, for the first time, ...

Microwave absorption measurements in magnetic fields from 0 up to 16 T were used to determine the temperature range of superconducting fluctuations above the superconducting critical temperature Tc in YBa2Cu3O7-?. Measurements were performed on deeply underdoped, slightly underdoped, and overdoped single crystals. The temperature range of the superconducting fluctuations above Tc is determined by ...

After an introductory discussion of electronic structure calculations for the CuO{sub 2} planes in the copper-oxide based high-{Tc} superconductors, the method suggested by Slater for studying antiferromagnetic (AF) metals is described. In this method, as applied here, the chemical unit cell is doubled to form a magnetic unit cell which contains one Cu ion with predominantly up spin and one with ...

We have measured the Hall mobility at room temperature in three samples of tetrathiafulvalenium-tetracyanoquinodimethanide (TTF-TCNQ), by means of a Faraday-rotation technique at 9.3 GHz, with the magnetic field normal to the a-b plane of the crystals. The Hall mobility, expressed as the drift mobility in the a direction multiplied by an enhancement factor eta, is observed to be positive, and eta ...

We report synthesis of phase pure multiferroic YMnO{sub 3} thin films on sapphire (0001) with conducting ZnGaO buffer contact layer. Films were prepared by using pulsed laser deposition technique and characterized using x-ray diffraction, scanning electron microscopy, energy dispersive absorption spectroscopy, and magnetic field dependent dielectric measurement techniques. ...

The temperature and magnetic field dependence of the in-plane thermal conductivity ? of the iron-arsenide superconductor Ba(Fe1-xCox)2As2 was measured down to T?50mK and up to H=15T as a function of Co concentration x in the range 0.048?x?0.114. At H=0, a negligible residual linear term in ?/T as T?0 at all x shows that the superconducting gap has no nodes in the ...

We have measured the critical current density j{sub c} as a function of the orientation of a magnetic field in vicinal YBa{sub 2}Cu {sub 3}O{sub 7{minus}{delta}} films. When both field and Lorentz force lie within the ab plane, we observe a minimum in j{sub c} . At high temperatures, as the c -axis coherence length approaches the ab ...

... Accession Number : ADD453883. Title : OPTICAL ABSORPTION AND CONDUCTIVITY STUDIES OF SENSITIZING DYES ON AGBR FILMS. ...

Bolometry was used obtain accurate submillimeter residual loss data for epitaxial films of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO), Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10}, Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} (TCBCO), and Ba{sub 0.6}K{sub 0.4}BiO{sub 3} (BKBO). We were able to fit the absorptivity measured for Nb films to an Eliashberg strong coupling calculation; excellent agreement resulted ...

... OPTICAL PROPERTIES, *CADMIUM TELLURIDES, *MERCURY COMPOUNDS ... NONLINEAR SYSTEMS, ALUMINUM, CONDUCTION BANDS ...

... the optical constants of intermetallic compound TiCo; The ... the optical conductivity of this compound and the ... structure of these compounds need an ...

Optical Metrology of the Optical Communications. Telescope Laboratory 1-Meter Telescope by. Means of Hartmann Tests Conducted at the Table Mountain ...

We report measurements of in-plane and out-of-plane fluctuation conductivity under low applied magnetic fields up to 500 Oe in two melt-textured YBa2Cu3O7?? (YBCO) samples. 3D-Gaussian and genuine critical 3D-XY-E fluctuation regimes were identified in the conductivity parallel to the ab plane. In addition, a ...

A physical property of a liquid or of any optical fiber is measured using optical fiber interferometer. A conductive material is disposed upon the surface of a region of a light transmitting optical fiber and the region having the conductive material is d...

An optical modulation device includes an electrolyte containing electrodepositable metal ions sandwiched between a conducting polymer counter electrode and an optical modulation electrode involving reversible metal electrodeposition. The conducting polyme...

Magnetization patterns on different faces of long bars cut from melt-processed YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) samples were studied using advanced magneto-optical techniques. It is shown that with an external magnetic field perpendicular to the long side of the bar the magnetization front is described by a cylindrical surface having a cross section shaped as a ...

... Nonlinear Optical properties, Polymer doping. Descriptors : *POLYMERS, *ELECTRICAL CONDUCTIVITY ... TRANSPORT, GLASS, NONLINEAR ...

... a technique for sealing electrically non-conductive optical windows to electrically ... destroying the optical properties of the window, particularly during ...

... In neither of the rod bundle nor rectangular bundle scans is there a fly back time in which the fiber optic components are not conducting, as in ...

... 4. TITLE AND SUBTITLE Acquisition of a magneto-optical cryostat for measurements of thermal conductivity in high magnetic fields ...

... Title : Thermal Conductivity Enhancement by Optical Phonon Sub-Band Engineering of Nanostructures Based on C and BN (CD-ROM). ...

... Accession Number : ADA209299. Title : Nonlinear Optical Properties of Conducting Polymers. Descriptive Note : Final rept. 1 Mar 1986-31 Mar 1989 ...

New ESA-formed optical, electrostrictive, conductive and abrasion resistant thin films have widespread applications in adaptive optical products for ...

The Optical Communications Group is the NASA's premiere Optical Communications ... AIST is conducting technology development activities leading to new ...

This document discloses an optical system which detects acoustical signals in a fluid medium such as seawater. Optical radiation such as from a laser is conducted to and from an optical-fiber, acoustical sensor assembly by use of one optical fiber or a pa...

Single crystals of (p-ClC{sub 6}H{sub 4}NH{sub 3})H{sub 2}PO{sub 4} are synthesized in water by interaction of H{sub 3}PO{sub 4} and (p-ClC{sub 6}H{sub 4}NH{sub 2}). This compound crystallizes in the orthorhombic system with the Pbca space group. Its unit-cell parameters are a = 9.724(3), b = 7.861(1), c = 25.078(6) A, V = 1917.1(6) A{sup 3} and Z = 8. The crystal structure has been solved and ...

... 84 3. CHARACTERIZATION AND OPTIMIZATION OF PHONO N THERMAL SPECTRA, CONDUCTIVITY AND SUPERCONDUCTIVITY 91 3.1. ...

further validated by comparison to thermal conductivity measurements using the ... thermal conductivity measurements as a function of temperature and pressure ...

Using meander line resonant structures, we perform highly sensitive measurements of the changes in surface resistance Delta R_{s} of Y{rm Ba}_{2} {rm Cu}_{3}{rm O }_{rm 7-x} thin films in order to probe vortex dynamics as a function of temperature, applied dc magnetic field (H), and angle (theta) of the applied field relative to the ab planes. In our ...

Aliovalent K(0.92)In(0.46)Nb(0.54)OPO(4) (KINP, potassium indium niobium oxide phosphate) features a chain structure involving corner-sharing [MO(6)] octahedra (M = In/Nb), which allows this compound to be recognized as a member of the KTiOPO(4) (KTP) family. However, its crystallization in the polar space group P4(1) belonging to the 4/m Laue group generates its own subclass of KTP-related ...

Crossed-magnetic-field effects on bulk high-temperature superconductors have been studied both experimentally and numerically. The sample geometry investigated involves finite-size effects along both (crossed-)magnetic-field directions. The experiments were carried out on bulk melt-processed Y-Ba-Cu-O single domains that had been premagnetized with the applied field parallel to their shortest ...

Organic electro-optic modulator using transparent conducting oxides as electrodes Guoyang Xu, Zhifu: A novel organic electro-optic (EO) modulator using transparent conducting oxides (ZnO and In2O3 Society of America OCIS codes: (190.4710) Optical nonlinearities in organic materials; (250.2080) ...

An uncertainty analysis is conducted for four asteroids with different optical and radar observation

... thermoelectric power, thermal conductivity, optical reflectivity, and absorption as functions of temperature are reported for magnetite and cobalt iron ...

... Abstract : A program was conducted to establish a process for the production of useful sizes of optically transparent ceramic armor. ...

... MOSSBAUER EFFECT, PHOTOCONDUCTIVITY, TRANSPORT PROPERTIES, ELECTRICAL CONDUCTIVITY, PHOTOELECTRIC EFFECT. ...

We use ac susceptibility to study the vortex pinning force anisotropy and the magnetic lock-in effect in the organic superconductor (TMTSF){sub 2}ClO{sub 4}, which is believed to have an in-plane anisotropy of {gamma}{sub {ital b}{ital a}}{similar_to}10 and a maximum out-of-plane anisotropy {gamma}{sub {ital c}{ital a}}{similar_to}100. Our measurements show only weak effects of the in-plane ...

We have measured, via simultaneous resistance and magnetization, the upper critical field in the organic superconductor (TMTSF)_2ClO4 for B exactly in the a-b plane, close to (along) the b� axis. We find agreement with our earlier results [1] for fields up to 3.5T, where the slope -dH_c2(T)/dT reaches about 8T/K. At higher field, we do not find evidence for reentrance, although the critical ...

The low-temperature antiferromagnetic state of the Sm ions in both nonsuperconducting SmFeAsO and superconducting SmFeAsO0.9F0.1 single crystals was studied by magnetic torque, magnetization, and magnetoresistance measurements in magnetic fields up to 60 T and temperatures down to 0.6 K. We uncover in both compounds a distinct rearrangement of the antiferromagnetically ordered Sm moments near ...

We have studied the role of pinning in the mixed-state thermomagnetic transport properties of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. We demonstrate the pinning independence of the transport entropy {ital S}{sub {phi}}, and its consequent scaling within an anisotropic mass model. Due to the anisotropy of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} the extrinsic pinning strength effectively ...

Interlayer BCS-like (Bardeen-Cooper-Schrieffer Theory) pairing in nearly two-dimensional superconductors with N = 1,2,3 conducting layers per unit cell is investigated. For N = 1, the singlet delta(sub s) and triplet delta(sub t), order parameters have identical T(sub c)'s (T(sub cs) = T(sub ct)) and magnitudes, and the gap is isotropic. For N = 2, T(sub cs) is greater than or ...

We have used both bolometric and cavity techniques to obtain accurate submillimeter and microwave loss data for epitaxial thin films of Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} at low temperatures. These films have {Tc}=121.5 K, are c-axis oriented, contain some volume fraction of the 2:1:2:2 phase, and are characterized by excellent in-plane epitaxy. The absorptivity of these films at 100 ...

Dielectric characteristics of Ba4Nd2Ti4Nb6O30 tungsten bronze ceramics have been investigated over a broad range of temperature and frequency. The real part of the dielectric constant (?') shows a sharp peak at 417 K indicating the ferroelectric phase transition. Two dielectric relaxations are observed in the lower temperature range, which are very obvious in the dielectric loss (tan ?) and the ...

BaPt has been synthesized by reaction of a 1:1 mixture of Ba and Pt at 1223 K in argon and characterized by single-crystal X-ray structure determination and electrical resistivity and magnetic susceptibility measurements. The compound crystallizes in the NiAs structure type with an extremely low value for the c/a ratio (hexagonal space group P6(3)/mmc with a = 5.057(2) A, c = 5.420(3) A, c/a = ...

?-YbAlB4 is the locally isostructural polymorph of ?-YbAlB4, the first example of a Yb-based heavy fermion superconductor that exhibits pronounced non-Fermi-liquid behavior above Tc. Interestingly, both ?-YbAlB4 and ?-YbAlB4 have strongly intermediate valence. Our single-crystal study of the specific heat, magnetization, and resistivity has confirmed the Fermi-liquid ground state of ?-YbAlB4 in ...

The Mo-V-Te-Nb-O mixed metal oxide catalyst possessing the M1 phase structure is uniquely capable of directly converting propane into acrylonitrile. However, the mechanism of this complex eight-electron transformation, which includes a series of oxidative H-abstraction and N-insertion steps, remains poorly understood. We have conducted a density functional theory study of ...

The charge-transfer salt [ (BEDT-TTF){4}] 2+[ Ni(dto){2}] 2- is a quasi two-dimensional organic metal [1]. This is confirmed by the resistivity ratio ? c/? (a,b)=100 at 300K, where (a,b) represents the high conducting plane. The material shows strong quantum oscillations (QOs) above about 1.2T (at 20mK) with two QO frequencies F{? }=634T and F{? }=4245T. We report on AMRO ...

It is usually assumed that high-T(c) superconductors have a periodic band structure and a periodic charge density, although amorphous low-T(c) superconductors are known. In this paper, it is suggested that the CuO(2) conduction planes of cuprate superconductors consist of regions of two different charge densities which do not normally repeat periodically. It is suggested that ...

Studies of the synthesis of organic polymers potentially possessing electrically conductive piezoelectric, and nonlinear optical properties are described. The electrically conducting polymer studies center on polyaromatic quinondiimines, analogs of the kn...

The optical tungsten bronze BSTN and BSKNN single crystals were investigated for photorefractive and guided wave optical applications with considerable success. These materials have both high optical figure of merit and low dark conductivity, making them ...

The NASA Lewis Research Center conducted a workshop on fiber optic technology on October 18-20, 1994. The workshop objective was to discuss the future direction of fiber optics and optical sensor research, especially in the aerospace arena. The workshop w...

This paper reports a neutron powder diffraction study of CaMn2Sb2 in the temperature range of 20-300 K. Short-range magnetic order, characterized by a broad diffraction peak corresponding to a d spacing of 4 , is observed between 120 and 200 K. Collinear long-range antiferromagnetic order of manganese ions occurs below 85 K, where a transition is observed in the DC magnetic susceptibility measured ...

The field amplitude and frequency dependent complex ac susceptibility ?(Hm, f) of four Y-Ba-Cu-O discs made by a top-seeded melt growth technique has been measured at 77 K with the ac field applied parallel to either the disc axis (the c axis of the grain) or its radius (the ab plane of the grain). The results are interpreted by considering the anisotropic ...

A Delphi study has been conducted in the field of aero-optics research and development. The study includes the system components of aerodynamics, optical materials, optical analytics, optical seekers, and aero-optical integration of the system components into an ...

In the title compound, C(4)H(8)N(2)O(3)�C(4)H(6)O(6), the amino acid mol-ecule exists as a zwitterion and the carb-oxy-lic acid in an un-ionized state. The tartaric acid mol-ecules are linked into layers parallel to the ab plane by O-H?O hydrogen bonds. The amino acid mol-ecules are also linked into layers parallel to the ab ...

Vortex matter of the layered superconductors in very high magnetic fields near the ab-plane was studied by using the c-axis resistivity measurements on the mesoscopic Bi2Sr2CaCu2O8+? single crystals. While the angular dependence of resistance exhibits the sharp lock-in features in low magnetic field region, it was found that the vortex lock-in transition becomes considerably broad in high magnetic ...

Bulk magnetically melt textured YBaCuO at 77 K shows critical current densities of up to 19000 A/cm[sup 2] in 20 teslas when the field is parallel to the (a,b) planes. The angular dependence of J[sub c] is shown to support a recent interpretation of the high superconducting transport currents measured above the irreversibility line in terms of intrinsic surface superconductivity. The behavior when ...

Measurements of the nonlinear flux-flow resistivity ? and the critical vortex velocity v?* at high voltage bias close to the instability regime predicted by Larkin and Ovchinnikov (Z. Eksp. Teor. Fiz 68, 1915 (1975) [Sov. Phys. JETP 41, 960 (1976)]) are reported along the node and antinode directions of the d-wave order parameter in the a-b plane of epitaxial YBa2Cu3O7-? films. In this ...

The measurements of temperature dependences of magnetic susceptibility both in (a-b) plane, and along c-axis of CaNdAlO{sub 4} single crystal have been performed. The strong uniaxial anisotropy of magnetic properties has been found. The low field susceptibility along c-axis is well described by the Curie law, while the susceptibility in (a-b) plane can be described by Curie-Weiss law suggesting ...

The colossal (more than threefold) decrease in the dielectric constant ? in the easy-plane SmFe3(BO3)4 ferroborate in a magnetic field of �5 kOe applied in the basal ab plane of the crystal has been found. A close relation of this effect to anomalies in the field dependence of the electric polarization has been established. It has been shown that this ...

Based on new theory of nonlinear optical conductivity for an electron � phonon system, we calculate line widths for the nonlinear optical conductivity in a system of electron interacting with longitudinal optical phonons (LO) in doped semiconductor superlattices (DSSL). Our numerical results ...

Low-Voltage Electro-Optic Modulator Structure using Transparent Conducting Oxide with High, 2145 Sheridan Rd, Evanston, IL, 60208 Abstract: We describe a novel design of electro-optical modulator interest in reducing the switching voltage of electro-optic (EO) modulator to

Using optical reflection microscopy we can locate and count graphene layers on a bulk glass substrate. This is a reliable and low cost technique for graphene flake metrology. Optical reflection measurements are in agreement with the universal optical conductance of graphene. We present measurements of the ...

The contribution of optical phonons to thermal conductivity has typically been ignored. However, when the system size decreases to the nanoscale regime, optical phonons are no longer negligible. In this study, the contributions of different phonon polarizations to the thermal conductivity of silicon are discussed ...

The electrical conductivity and optical properties of fluorescein sodium salt in the temperature range of 295 370 K have been investigated. Various conduction models described in the literature were used to elucidate the charge transport mechanism of the compound. It is found that the charge transfer mechanism of the compound is ...

A light transmitting electrically conductive stacked film, useful as a light transmitting electrode, including a first light transmitting electrically conductive layer, having a first optical thickness, a second light transmitting layer, having a second optical thickness different from the ...

The purpose of this program is to conduct research toward the development of a tunable coherent source based on nonlinear optical effects, to demonstrate a tunable coherent light source, and to demonstrate parametric gain at optical frequencies. Work was ...

... One end of branes, the fluorophor was also dissolved in ... The only fluorophor that showed promise branes were conducted with a fiber optic pho- ...

Large optics used in high power chemical lasers are expensive and require cooling. (CTE, thermal conductivity, MLD issues). High power solid state laser ...

An explanation of the electroless nickel plating process is given and important metallurgical and mechanical properties of the plating are discussed. Optical applications of electroless nickel are described. Machinability tests were conducted with variati...

A number of systematic experiments were conducted on the fluoride optical glasses, primarily glasses of the fluoride-phosphate systems. The vitrification regions for these glasses were determined, and their physicochemical properties, such as refractive i...