Sample records for xrd hrtem magnetic

  1. XRD, SEM, AFM, HRTEM, EDAX and RBS studies of chemically deposited Sb 2S 3 and Sb 2Se 3 thin films

    Microsoft Academic Search

    C. D Lokhande; B. R Sankapal; R. S Mane; H. M Pathan; M Muller; M Giersig; V Ganesan

    2002-01-01

    Nanocrystalline thin films of Sb2S3 and Sb2Se3 are obtained at low temperature by simple chemical deposition method. The preparative parameters are optimized to get nanocrystalline films. The films are characterized for structural, surface morphological and compositional analyses by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), high-resolution transmission electron micrograph (HRTEM), energy-dispersive X-ray analyses (EDAX)

  2. HRTEM, SAED and XRD investigations of RE{sub 4}O{sub 4}[AsO{sub 4}]Cl (RE = La, Pr, Nd, Sm, Eu, Gd)

    SciTech Connect

    Ben Yahia, Hamdi, E-mail: benyahia.hamdi@voila.fr [Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstrasse 30, D-48149 Münster (Germany); Rodewald, Ute Ch. [Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstrasse 30, D-48149 Münster (Germany); Boulahya, Khalid [Departamento de Química Inorgánica Facultad de Químicas Universidad Complutense, 28040 Madrid (Spain); Pöttgen, Rainer [Institut für Anorganische und Analytische Chemie, Universität Münster, Corrensstrasse 30, D-48149 Münster (Germany)

    2014-05-01

    Graphical abstract: The new compounds RE{sub 4}O{sub 4}[AsO{sub 4}]Cl (RE = La, Pr, Nd, Sm, Eu, Gd) were synthesised by solid state reaction via a salt flux route and investigated by HRTEM, SAED, and single crystal X-ray diffraction. - Highlights: • We discovered the series of RE{sub 4}O{sub 4}[AsO{sub 4}]Cl (RE = La, Pr, Nd, Sm, Eu, Gd) compounds. • The RE{sub 4}O{sub 4}[AsO{sub 4}]Cl single crystals were grown using NaCl/KCl flux. • The RE{sub 4}O{sub 4}[AsO{sub 4}]Cl structures were solved using single crystal X-ray diffraction data. • The layered RE{sub 4}O{sub 4}[AsO{sub 4}]Cl compounds were further characterized using HRTEM and SAED. • We observed an alternation of ordered-[RE{sub 4}O{sub 4}]{sup 4+} and disordered-[ClAsO{sub 4}]{sup 4–} layers. - Abstract: The new compounds RE{sub 4}O{sub 4}[AsO{sub 4}]Cl (RE = La, Pr, Nd, Sm, Eu, Gd) were synthesised by solid state reaction via a salt flux route and investigated by HRTEM, SAED, and single crystal X-ray diffraction. The samples crystallise with a tetragonal cell, space group P4{sub 2}/mnm and Z = 2. Their crystal structure consists of an alternation of [RE{sub 4}O{sub 4}]{sup 4+} and [ClAsO{sub 4}]{sup 4–} layers. The [RE{sub 4}O{sub 4}]{sup 4+} layer contains ORE{sub 4/4} tetrahedra which share common edges. The anions AsO{sub 4}{sup 3–} and Cl{sup –} are located between these layers in disordered manner. SAED and HRTEM experiments confirmed this structural model and enabled us to propose an ordered model for the [ClAsO{sub 4}]{sup 4–} layers.

  3. Magnetic composites from minerals: study of the iron phases in clay and diatomite using Mössbauer spectroscopy, magnetic measurements and XRD

    NASA Astrophysics Data System (ADS)

    Cabrera, M.; Maciel, J. C.; Quispe-Marcatoma, J.; Pandey, B.; Neri, D. F. M.; Soria, F.; Baggio-Saitovitch, E.; de Carvalho, L. B.

    2014-01-01

    Magnetic particles as matrix for enzyme immobilization have been used and due to the enzymatic derivative can be easily removed from the reaction mixture by a magnetic field. This work presents a study about the synthesis and characterization of iron phases into magnetic montmorillonite clay (mMMT) and magnetic diatomaceous earth (mDE) by 57Fe Mössbauer spectroscopy (MS), magnetic measurements and X-ray diffraction (XRD). Also these magnetic materials were assessed as matrices for the immobilization of invertase via covalent binding. Mössbauer spectra of the magnetic composites performed at 4.2 K showed a mixture of magnetite and maghemite about equal proportion in the mMMT, and a pure magnetite phase in the sample mDE. These results were verified using XRD. The residual specific activity of the immobilized invertase on mMMT and mDE were 83 % and 92.5 %, respectively. Thus, both magnetic composites showed to be promising matrices for covalent immobilization of invertase.

  4. Nanoscale chemical and structural study of Co- based FEBID structures by STEM-EELS and HRTEM

    E-print Network

    Cordoba, Rosa; Fernandez-Pacheco, Rodrigo; Fernandez-Pacheco, Amalio; Gloter, Alexandre; Magen, Cesar; Stephan, Odile; Ricardo Ibarra, Manuel; De Teresa, Jose Maria

    2011-11-15

    NANO EXPRESS Open Access Nanoscale chemical and structural study of Co- based FEBID structures by STEM-EELS and HRTEM Rosa Córdoba1,2, Rodrigo Fernández-Pacheco1,3, Amalio Fernández-Pacheco1,2, Alexandre Gloter3, César Magén1,2,4, Odile Stéphan3... electron microscopy at the nanometric scale. The obtained results allow us to correlate the chemical and structural properties with the functionality of these magnetic nanostructures. Keywords: Co deposits, FEBID, EELS, HRTEM Background Despite its great...

  5. Comparison of schemes for preparing magnetic Fe 3O 4 nanoparticles

    Microsoft Academic Search

    Ruoyu Hong; Jianhua Li; Jian Wang; Hongzhong Li

    2007-01-01

    Magnetic Fe3O4 nanoparticles were prepared by means of coprecipitation using NH3·H2O in water and in alcohol, and using NaOH in water. A series of instruments such as SEM, TEM, HRTEM, FT-IR, XRD and VSM were used to characterize the properties of the magnetic nanoparticles. The results indicated that the magnetism of Fe3O4 nanoparticles synthesized using NH3·H2O in water was the

  6. Analysis Request Form MALDI MS CRM HRTEM MICROTOME

    E-print Network

    Bhashyam, Srikrishna

    Analysis Request Form MALDI MS CRM HRTEM MICROTOME Internal External Request number (For technician Preferred matrix (only for MALDI MS) 1. 2. *Only high vacuum compatible samples will be analysed in MALDI)................................................................................................ Per unit charge Nature of Analysis TEM CRM MALDI MICROTOME Assisted 500 400 350 250 Unassisted* 400

  7. Direct evidence of chemical ordering in the FePt nanostructured alloy by HR-TEM

    NASA Astrophysics Data System (ADS)

    Gupta, Rekha; Medwal, Rohit; Annapoorni, S.

    2015-07-01

    The iron-platinum (FePt) alloy exhibits structural and magnetic phase transformation even at a low temperature of 300 °C with an insignificant grain growth. These transformation studies were understood nano-scopically using high resolution-transmission electron microscopy (HR-TEM). The FePt grains show strain induced structural transformation and adopts polycrystalline behaviour. The chemical ordering of FePt grains is explained using Fast Fourier Transform (FFT) analysis of the TEM image. HR-TEM image shows the hexagonal arrangement of Pt atoms in the [0 0 1] direction in the FePt unit cell which gives the direct evidence of chemical ordering in FePt nanostructured alloy. The filtration and reconstruction method has been employed with the help of inverse Fast Fourier Transformation tool, confirming the formation of L10 FePt phase. The chemical ordering is also confirmed by structural and magnetic measurements revealing an order parameter of 0.875 and coercivity 3 kOe respectively at a low annealing temperature of 300 °C. The chemical ordering at low annealing temperature makes it suitable for media storage applications.

  8. MEGACELL: a nanocrystal model construction software for HRTEM multislice simulation.

    PubMed

    Stroppa, Daniel G; Righetto, Ricardo D; Montoro, Luciano A; Ramirez, Antonio J

    2011-07-01

    Image simulation has an invaluable importance for the accurate analysis of High Resolution Transmission Electron Microscope (HRTEM) results, especially due to its non-linear image formation mechanism. Because the as-obtained images cannot be interpreted in a straightforward fashion, the retrieval of both qualitative and quantitative information from HRTEM micrographs requires an iterative process including the simulation of a nanocrystal model and its comparison with experimental images. However most of the available image simulation software requires atom-by-atom coordinates as input for the calculations, which can be prohibitive for large finite crystals and/or low-symmetry systems and zone axis orientations. This paper presents an open source citation-ware tool named MEGACELL, which was developed to assist on the construction of nanocrystals models. It allows the user to build nanocrystals with virtually any convex polyhedral geometry and to retrieve its atomic positions either as a plain text file or as an output compatible with EMS (Electron Microscopy Software) input protocol. In addition to the description of this tool features, some construction examples and its application for scientific studies are presented. These studies show MEGACELL as a handy tool, which allows an easier construction of complex nanocrystal models and improves the quantitative information extraction from HRTEM images. PMID:21740871

  9. A HRTEM\\/EDX approach to identification of the source of dust particles on urban tree leaves

    Microsoft Academic Search

    S. G. Lu; Y. W. Zheng; S. Q. Bai

    2008-01-01

    Dust on tree leaves in the urban area of Hangzhou, China, was analyzed in terms of heavy metal contents and magnetic properties. Morphological and chemical composition of the dust particles were analyzed using a high resolution transmission electron microscope equipped with an energy-dispersive X-ray analyzer (HRTEM\\/EDX). Results indicated that the dusts contained high concentrations of Cd (mean 2.62), Cu (63.7),

  10. Survey of basic XRD applications.

    SciTech Connect

    Rodriguez, Mark Andrew

    2010-07-01

    This 1/2 day workshop will survey various applications of XRD analysis, including in-situ analyses and neutron diffraction. The analyses will include phase ID, crystallite size and microstrain, preferred orientation and texture, lattice parameters and solid solutions, and residual stress. Brief overviews of high-temperature in-situ analysis, neutron diffraction and synchrotron studies will be included.

  11. Synthesis and electro-magnetic properties of flower-like Fe2O3-Ag nanocomposite using direct subsidence loading method

    NASA Astrophysics Data System (ADS)

    Zhou, Xing; Wu, Zhengying; Xu, Nan; Liu, Shouqing; Zhao, Guizhe; Liu, Yaqing

    2015-10-01

    Novel flower-like Fe2O3/Ag nanocomposites were synthesized by a simple direct subsidence loading method. The composition and morphology of the obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SEAD) techniques. The Ag nanoparticles which loaded on the surface of petals exhibit spherical morphology. Further, the magnetic and electrical conductive properties reveal the well controllable performance. Room temperature magnetic measurement of the flower-like nanocomposites demonstrated its ferromagnetic properties and the saturation magnetization (Ms) decreased from 0.6 to 0.11 emu/g.

  12. Ceramic/metal nanocomposites by lyophilization: Processing and HRTEM study

    SciTech Connect

    Gutierrez-Gonzalez, C.F. [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo Superior de Investigaciones Cientificas - CSIC - Universidad de Oviedo - UO - Principado de Asturias - PA, Parque Tecnologico de Asturias, 33428 Llanera (Spain)] [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo Superior de Investigaciones Cientificas - CSIC - Universidad de Oviedo - UO - Principado de Asturias - PA, Parque Tecnologico de Asturias, 33428 Llanera (Spain); Agouram, S. [Department of Applied Physics and Electromagnetism, Universitat de Valencia, 46100 Burjassot (Spain)] [Department of Applied Physics and Electromagnetism, Universitat de Valencia, 46100 Burjassot (Spain); Torrecillas, R. [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo Superior de Investigaciones Cientificas - CSIC - Universidad de Oviedo -UO - Principado de Asturias- PA, Parque Tecnologico de Asturias, 33428 Llanera (Spain)] [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo Superior de Investigaciones Cientificas - CSIC - Universidad de Oviedo -UO - Principado de Asturias- PA, Parque Tecnologico de Asturias, 33428 Llanera (Spain); Moya, J.S. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (ICMM-CSIC), Cantoblanco, 28049 Madrid (Spain)] [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas (ICMM-CSIC), Cantoblanco, 28049 Madrid (Spain); Lopez-Esteban, S., E-mail: s.lopez@cinn.es [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Consejo Superior de Investigaciones Cientificas - CSIC - Universidad de Oviedo - UO - Principado de Asturias - PA, Parque Tecnologico de Asturias, 33428 Llanera (Spain)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer A cryogenic route has been used to obtain ceramic/metal nanostructured powders. Black-Right-Pointing-Pointer The powders present good homogeneity and dispersion of metal. Black-Right-Pointing-Pointer The metal nanoparticle size distributions are centred in 17-35 nm. Black-Right-Pointing-Pointer Both phases, ceramic and metal, present a high degree of crystallinity. Black-Right-Pointing-Pointer Good metal/ceramic interfaces due to epitaxial growth, studied by HRTEM. -- Abstract: This work describes a wet-processing route based on spray-freezing and subsequent lyophilization designed to obtain nanostructured ceramic/metal powders. Starting from the ceramic powder and the corresponding metal salt, a water-based suspension is sprayed on liquid nitrogen. The frozen powders are subsequently freeze-dried, calcined and reduced. The material was analyzed using X-ray diffraction analysis at all stages. High resolution transmission electron microscopy studies showed a uniform distribution of metal nanoparticles on the ceramic grain surfaces, good interfaces and high crystallinity, with an average metal particle size in the nanometric range.

  13. In-situ synthesis of magnetic (NiFe 2O 4/CuO/FeO) nanocomposites

    NASA Astrophysics Data System (ADS)

    Srivastava, Manish; Ojha, Animesh K.; Chaubey, S.; Singh, Jay

    2010-11-01

    In-situ synthesis of magnetic nanocomposites with (NiFe 2O 4/CuO/FeO) crystal phases has been done using a sol-gel method by taking a non-stoichiometric composition of the precursors. The average particle size of the nanocomposites was calculated using X-ray diffraction (XRD) and high resolution tunneling electron microscope (HR-TEM) and it turns out to be ˜20 nm. The vibrating sample magnetometer (VSM) measurements demonstrate the ferromagnetic nature of the nanocomposites. The synthesized nanocomposite was used to prepare magnetic fluid using tetramethylammonium hydroxide as a surfactant and its stability in the solution was also discussed.

  14. Structure analysis of CVD graphene films based on HRTEM contrast simulations

    Microsoft Academic Search

    Paul Plachinda; Sergei Rouvimov; Raj Solanki

    2011-01-01

    Low-voltage, aberration-corrected, High-Resolution Transmission Electron Microscopy (HRTEM) has proven to be an excellent tool for structure analysis of graphene films, which are typically one or a few atoms thick. Experimental observations of graphene films by HRTEM exhibit several challenges due to low contrast and sensitivity of graphene to intense electron beams. Hence the contrast interpretation requires computer simulations for reliable

  15. Structure, morphology and magnetic properties of Fe Au core-shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Pana, O.; Teodorescu, C. M.; Chauvet, O.; Payen, C.; Macovei, D.; Turcu, R.; Soran, M. L.; Aldea, N.; Barbu, L.

    2007-09-01

    The aim of the present work is the investigation of the core-shell Fe@Au nanoparticles obtained by the inverse micelles method. Also hybrid structures between Fe@Au nanoparticles and the well-known conducting polymer polypyrrole (PPY) were obtained and investigated. The properties of the composites were investigated by TEM, HRTEM, X-ray diffraction (XRD), X-ray Photoelectron spectroscopy (XPS) and magnetization measurements. The TEM, HRTEM measurements show that two categories of core-shell nanoparticles with mean diameters of 5 nm and 25 nm, respectively, are formed. The XPS investigations of the core-shell Fe@Au nanoparticles indicate that besides Fe 0 inside the cores, small amounts of Fe II,III, located onto the gold surface ,were also formed during the samples preparation. The magnetization of the investigated nanocomposites measured versus increasing and decreasing magnetic field shows no hysteresis loop, this behavior being consistent with a superparamagnetic behavior. The behavior of the SQUID magnetization vs. temperature under field cooled (FC) and zero field cooled (ZFC) at 0.1 T magnetic field for Fe@Au nanoparticles confirmed the existence of superparamagnetism. The superparamagnetic model was used to fit the experimental magnetization vs. applied magnetic field as it was measured by SQUID up to 5 T.

  16. A HRTEM/EDX approach to identification of the source of dust particles on urban tree leaves

    NASA Astrophysics Data System (ADS)

    Lu, S. G.; Zheng, Y. W.; Bai, S. Q.

    Dust on tree leaves in the urban area of Hangzhou, China, was analyzed in terms of heavy metal contents and magnetic properties. Morphological and chemical composition of the dust particles were analyzed using a high resolution transmission electron microscope equipped with an energy-dispersive X-ray analyzer (HRTEM/EDX). Results indicated that the dusts contained high concentrations of Cd (mean 2.62), Cu (63.7), Zn (535.9) and Pb (150.9 mg kg -1). Magnetic susceptibility of the dusts was in a range of (16-856) × 10 -8 m 3 kg -1. It was shown that the dusts close to industrial area and busy road intersection had higher heavy metal contents and magnetic susceptibility. The dusts showed a strong positive inter-correlation for the concentrations of Fe, Mn, Cr, Zn, Pb, and Cu in addition to magnetic susceptibility, which suggests that the dusts had a common source for the heavy metals and magnetic carriers. We found that the dust particles were composed mainly of Fe-rich near-spherical, plate and agglomerate particles, and Ca-rich, S-rich and silicate particles, and that iron oxide spherules (0.2-0.5 ?m in diameter) and larger iron-bearing particles were the magnetic carriers. Ca in the dusts was present in the forms of CaCO 3 and CaCO 3/CaSO 4 internal mixture. The Fe-rich, Ca-rich and S-rich particles in dusts could be directly related to nearby polluting activities, such as coal combustion, traffic emission and industrial activity. The identification of the main sources of dusts on tree leaves can help in controlling the polluting sources in urban areas. The close correlation between magnetic susceptibility and heavy metal concentration makes it possible to use the magnetic technique as a non-destructive and time-efficient tool for biomonitoring of the atmospheric dust pollutants.

  17. HRTEM study of zircon from Eliseev anorthosite complex, Antarctica

    SciTech Connect

    Wirth, R.; Kaempf, H. [GeoForschungsZentrum Potsdam (Germany); Hoehndorf, A. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany)

    1996-12-31

    Zircon-bearing rocks of this study are metamorphic oxide-apatite gabbronorites (OAGN) from the Eliseev Anorthosite Complex, Wohlthat-Massif, East Antarctica. These unusual rocks are strongly enriched in accessory minerals apatite: <10 vol.%; zircon: < 1 vol.. Three steps in the evolution of these rocks are distinguished: a magnetic formation, followed by a granulite facies metamorphism and finally a tectonomagmatic overprint. The zircon crystals of this study are brown colored, up to 12 mm in length and up to 3 mm wide. Petrological investigations show that zircon has formed during the granulite facies event. Optical microscopy and cathodoluminiscence microscopy reveal a rhythmic zoning and many microcracks. The concentrations of uranium and thorium are low (U: 34-89 ppm and Th: 3-9 ppm). The radiation damage by radioactive decay of U and Th is expected to be minor due to the low uranium and thorium content. The investigations were carried out in a Philips CM200 transmission electron microscope. Analytical electron microscopy was performed by energy dispersive analysis (EDAX).

  18. Magnetic photocatalysts with a p-n junction: Fe3O4 nanoparticle and FeWO4 nanowire heterostructures.

    PubMed

    Cao, Xuan; Chen, Yan; Jiao, Shihui; Fang, Zhenxing; Xu, Man; Liu, Xu; Li, Lu; Pang, Guangsheng; Feng, Shouhua

    2014-11-01

    Magnetic n-type semiconductor Fe3O4 nanoparticle and p-type semiconductor FeWO4 nanowire heterostructures were successfully synthesized without any surfactants or templates via a facile one-step hydrothermal process at 160 °C. The heterojunction structure and morphology were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Magnetic measurements indicated the coexistence of ferrimagnetic behavior of Fe3O4 and weak antiferromagnetic behavior of FeWO4. The degradation of methylene blue (MB) under UV-Visible light irradiation was studied as a model experiment to evaluate the catalytic activity of the Fe3O4/FeWO4 heterostructure p-n junctions. The decomposition efficiency was 97.1% after one hour UV-Visible irradiation. This magnetic photocatalyst can be easily recovered from the solution using a permanent magnet and redispersed by removing the magnet. PMID:25201551

  19. A Tool for Local Thickness Determination and Grain Boundary Characterization by CTEM and HRTEM Techniques.

    PubMed

    Kiss, Ákos K; Rauch, Edgar F; Pécz, Béla; Szívós, János; Lábár, János L

    2015-04-01

    A new approach for measurement of local thickness and characterization of grain boundaries is presented. The method is embodied in a software tool that helps to find and set sample orientations useful for high-resolution transmission electron microscopic (HRTEM) examination of grain boundaries in polycrystalline thin films. The novelty is the simultaneous treatment of the two neighboring grains and orienting both grains and the boundary plane simultaneously. The same metric matrix-based formalism is used for all crystal systems. Input into the software tool includes orientation data for the grains in question, which is determined automatically for a large number of grains by the commercial ASTAR program. Grain boundaries suitable for HRTEM examination are automatically identified by our software tool. Individual boundaries are selected manually for detailed HRTEM examination from the automatically identified set. Goniometer settings needed to observe the selected boundary in HRTEM are advised by the software. Operation is demonstrated on examples from cubic and hexagonal crystal systems. PMID:25801740

  20. HRTEM and X-ray diffraction analysis of Au wire bonding interface in microelectronics packaging

    NASA Astrophysics Data System (ADS)

    Junhui, Li; Ruishan, Wang; Lei, Han; Fuliang, Wang; Zhili, Long

    2011-01-01

    Interfacial microstructures of thermosonic Au wire bonding to an Al pad of die were investigated firstly by high-resolution transmission electron microscopy (HRTEM) and X-ray micro-diffractometer. The equal-thickness interference structures were observed by HRTEM due to diffusion and reaction activated by ultrasonic and thermal at the Au/Al bond interface. And X-ray diffraction results showed that three different interplanar crystal spacings ('d' value) of the interfacial microstructures were 2.2257 Å, 2.2645 Å, and 2.1806 Å respectively from the high intensity of diffraction to the low intensity of diffraction. These indicated that the intermetallic phase AlAu 2 formed within a very short time. It would be helpful to further research wire bonding technology.

  1. HRTEM Study of yttrium oxide particles in ODS steels for fusion reactor application

    Microsoft Academic Search

    M. Klimiankou; R. Lindau; A. Möslang

    2003-01-01

    An oxide dispersion strengthened ferritic-martensitic steel with yttrium oxide (Y2O3) was produced by mechanical alloying and hot isostatic pressing techniques for high-performance structures of fusion energy devices. The structure of the nanometer-sized Y2O3 particles analysed by HRTEM shows a strong correlation of its crystallographic orientation with the alloy lattice. The orientation correlations [110]YO?[111]FeCr and (11?1?)YO?(11?0)FeCr were found. The strong orientation

  2. Synthesis, Characterization and Studies on Optical, Dielectric and Magnetic Properties of undoped and Cobalt doped Nanocrystalline Bismuth Ferrite

    NASA Astrophysics Data System (ADS)

    Sarkar, K.; Mukherjee, Soumya; Mukherjee, S.; Mitra, M. K.

    2014-10-01

    Multiferroic perovskite nanocrystalline Bismuth ferrite (BFO) and Co doped Bismuth ferrite are synthesized by chemical route annealed at 500, 550 and 600 °C. XRD studies revealed the phases formed during synthesis while crystallite size is calculated in the range of 15.4-55 nm by Scherrer's formula from the identified XRD major peaks. The FTIR spectra of undoped BFO sample synthesized at 500, 550 and 600 °C exhibits clear presence of peaks at 554 cm-1 confirms the existence of Bi-O, Fe-O stretching and bending behavior of two different M-O co-ordination using Shimadzu-8400S Spectroscopy. The microstructure, lattice image and interplanar spacing are obtained by HRTEM analysis. The particle sizes are also measured from HRTEM while the chemistry is verified by energy dispersive x-ray analysis (EDX) (Oxford Instruments, INCA). Dielectric properties are observed for both undoped and Co doped samples. The band gap energy is measured by UV-VIS characterization using Tauc equation. Magnetic measurements are carried out using Physical Properties Measurement systems.

  3. Synthesis, Characterization and Studies on Optical, Dielectric and Magnetic Properties of undoped and Cobalt doped Nanocrystalline Bismuth Ferrite

    NASA Astrophysics Data System (ADS)

    Sarkar, K.; Mukherjee, Soumya; Mukherjee, S.; Mitra, M. K.

    2014-09-01

    Multiferroic perovskite nanocrystalline Bismuth ferrite (BFO) and Co doped Bismuth ferrite are synthesized by chemical route annealed at 500, 550 and 600 °C. XRD studies revealed the phases formed during synthesis while crystallite size is calculated in the range of 15.4-55 nm by Scherrer's formula from the identified XRD major peaks. The FTIR spectra of undoped BFO sample synthesized at 500, 550 and 600 °C exhibits clear presence of peaks at 554 cm-1 confirms the existence of Bi-O, Fe-O stretching and bending behavior of two different M-O co-ordination using Shimadzu-8400S Spectroscopy. The microstructure, lattice image and interplanar spacing are obtained by HRTEM analysis. The particle sizes are also measured from HRTEM while the chemistry is verified by energy dispersive x-ray analysis (EDX) (Oxford Instruments, INCA). Dielectric properties are observed for both undoped and Co doped samples. The band gap energy is measured by UV-VIS characterization using Tauc equation. Magnetic measurements are carried out using Physical Properties Measurement systems.

  4. Swelling of ion-irradiated 3C-SiC characterized by synchrotron radiation based XRD and TEM

    NASA Astrophysics Data System (ADS)

    Lin, Yan-Ru; Ho, Chun-Yu; Chuang, Wei-Tsung; Ku, Ching-Shun; Kai, Ji-Jung

    2014-12-01

    An experimental technique was established to characterize irradiation-induced volume swelling through a combined utilization of synchrotron radiation-based X-ray diffraction (XRD) and transmission electron microscopy (TEM). 3C-SiC specimens were irradiated by Si2+ ions (5 MeV) with fluences up to 5 × 1017 ion/cm2 at 1000 °C. In order to avoid the accumulation of implanted Si ions in the SiC layer, specific thicknesses of the epitaxy layer and implanted ion energy were chosen. Unresolvable black spot defects were studied by TEM, and the average size and density were calculated. XRD radial scan results of surface (0 0 2), (1 1 1), (0 2 2), (1 1 3), and (2 0 0) including peak shift and asymmetry peak broadening were observed. Different interplanar spacing information of single crystal SiC can be obtained from this XRD measurement method, making it possible to investigate the lattice expansion and volume swelling more precisely. While TEM provided a direct visualization of the microstructures and the interplanar spacing was measured from HRTEM images. It is suggested that irradiation induced point defects and compressive stress from the Si substrate were the cause of anisotropic (a = b < c) volume swelling of irradiated 3C-SiC in this study.

  5. A HRTEM study on serpentinized peridotite from the Southwest Indian Ridge and implications for the deep ocean hydrothermal system

    NASA Astrophysics Data System (ADS)

    Chen, T.; Jin, Z.; Li, W.; Li, H.

    2013-12-01

    Abyssal peridotites generate at mid-ocean ridges. Along the Earth's mid-ocean ridges, abyssal peridotites undergo hydration reactions to become serpentinite minerals, especially in slow to ultraslow spreading mid-ocean ridges. The Southwest Indian Ridge (SWIR) is one of the two ultraslow spreading ridges in the world. The studied serpentinized peridotite sample was collected by the 21st Voyage of the Chinese oceanic research ship Dayang Yihao (aka Ocean No. 1) from a hydrothermal field (63.5°E, 28.0°S, and 3660 m deep) in SWIR. Serpentinized reaction has attracted increasing attention as they are an expression of mantle hydration and water cycles in the deep Earth. There are three main types of serpentinite, antigorite (forms at T > 300°c ), lizadite (forms at T < 200°c ), and chrysotile (forms at intermediate temperatures) [1]. The mineral assemblages of the SWIR serpentinized peridotite was determined by petrography and XRD techniques, which comprises lizardite, chrysotile, olivine, orthopyroxene, clinopyroxene, spinel, magnetite, and chlorite. From SEM and TEM study, serpentinized olivine and orthopyroxene were found changed to chrysotile. However, seldom lizadite was found coexisting with chrysotile in clinopyroxene. From nanobeam SAED and HRTEM analysis, it was observed that the topological structure between lizadite and clinopyroxene is [100]cpx//[001]liz, while there is no topological relationship between chrysotile and clinopyroxene. A little chlorite was observed in serpentine vein, and some nanometer-sized amphibole was observed existing at the side of serpentine vein with [100]cpx//[001]amp. Chrysotile is the dominant serpentine mineral composition in this sample, which is different from most seafloor serpentinized peridotite [2]. The coexistence of chrysotile and lizadite indicates hydration temperature below 300°c , while the existence of chlorite and amphibole suggest hydration temperature reaching greenschist facies conditions, i.e. above 300°c, in the east part of SWIR [1, 2]. Acknowledgments: This work was supported by NSFC (41172050) and CSC. The electron microscopy was accomplished at the Electron Microscopy Center at Argonne National Laboratory, a U.S. Department of Energy Office of Science Laboratory operated under Contract No. DE-AC02-06CH11357 by UChicago Argonne, LLC. References [1] O'Hanley, D.S. Serpentinites. 1984. [2] Mével, C., Geoscience, 335:825, 2003.

  6. First Observation of InxGa1[minus sign]xAs Quantum Dots in GaP by Spherical-Aberration-Corrected HRTEM in Comparison with ADF-STEM and Conventional HRTEM

    NASA Astrophysics Data System (ADS)

    Tanaka, Nobuo; Yamasaki, Jun; Fuchi, Shingo; Takeda, Yoshikazu

    2004-02-01

    InxGa1[minus sign]xAs quantum dots in GaP(100) crystals prepared by the OMVPE technique are observed along the [011] direction with a newly developed 200-kV spherical aberration(Cs)-corrected HRTEM, a 200-kV annular dark-field (ADF)-STEM, and a 200-kV conventional HRTEM equipped with a thermal field-emission gun. The dots are 6 10 nm in size and strongly strained due to the misfit of about 9% with the GaP substrate and GaP cap layer. All of the cross-sectional high-resolution electron micrographs show dumbbell images of Ga and P atomic columns separated by 0.136 nm in well-oriented and perfect GaP areas, but the interpretable images are limited to those taken with the Cs-corrected HRTEM and ADF-STEM with Fourier filtering of the images. The Cs-corrected HRTEM and ADF-STEM are comparable from the viewpoint of interpretable resolution. A detailed comparison between the Cs-corrected HRTEM images and the simulated ones with electron incidence tilted by 1° to 5° from the [011] zone axis gives information on local lattice bending in the dots from the images around 0.1 nm resolution. This becomes one of the useful techniques newly available from electron microscopy with sub-Ångstrom resolution.

  7. In-situ synthesis of magnetic (NiFe{sub 2}O{sub 4}/CuO/FeO) nanocomposites

    SciTech Connect

    Srivastava, Manish [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad 211004 (India); Ojha, Animesh K., E-mail: animesh_r1776@rediffmail.co [School of Engineering and Science, Jacobs University, 28759 Bremen (Germany); Chaubey, S. [Department of Physics, Motilal Nehru National Institute of Technology, Allahabad 211004 (India); Singh, Jay [Department of Chemistry, Motilal Nehru National Institute of Technology, Allahabad 211004 (India)

    2010-11-15

    In-situ synthesis of magnetic nanocomposites with (NiFe{sub 2}O{sub 4}/CuO/FeO) crystal phases has been done using a sol-gel method by taking a non-stoichiometric composition of the precursors. The average particle size of the nanocomposites was calculated using X-ray diffraction (XRD) and high resolution tunneling electron microscope (HR-TEM) and it turns out to be {approx}20 nm. The vibrating sample magnetometer (VSM) measurements demonstrate the ferromagnetic nature of the nanocomposites. The synthesized nanocomposite was used to prepare magnetic fluid using tetramethylammonium hydroxide as a surfactant and its stability in the solution was also discussed. -- Graphical abstract: Magnetic nanocomposites containing (NiFe{sub 2}O{sub 4}/CuO/FeO) phases having particle size {approx}17 nm were synthesized by a sol-gel method. The synthesized nanocomposites exhibit ferromagnetic nature with small value of coercivity.

  8. First Observation of InxGa1[minus sign]xAs Quantum Dots in GaP by Spherical-Aberration-Corrected HRTEM in Comparison with ADF-STEM and Conventional HRTEM

    Microsoft Academic Search

    Nobuo Tanaka; Jun Yamasaki; Shingo Fuchi; Yoshikazu Takeda

    2004-01-01

    InxGa1[minus sign]xAs quantum dots in GaP(100) crystals prepared by the OMVPE technique are observed along the [011] direction with a newly developed 200-kV spherical aberration(Cs)-corrected HRTEM, a 200-kV annular dark-field (ADF)-STEM, and a 200-kV conventional HRTEM equipped with a thermal field-emission gun. The dots are 6 10 nm in size and strongly strained due to the misfit of about 9%

  9. Aloe vera plant-extracted solution hydrothermal synthesis and magnetic properties of magnetite (Fe3O4) nanoparticles

    NASA Astrophysics Data System (ADS)

    Phumying, Santi; Labuayai, Sarawuth; Thomas, Chunpen; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan; Maensiri, Santi

    2013-06-01

    Magnetite (Fe3O4) nanoparticles have been successfully synthesized by a novel hydrothermal method using ferric acetylacetonate (Fe(C5H8O2)3) and aloe vera plant-extracted solution. The influences of different reaction temperatures and times on the structure and magnetic properties of the synthesized Fe3O4 nanoparticles were investigated. The synthesized nanoparticles are crystalline and have particle sizes of ˜6-30 nm, as revealed by transmission electron microscopy (TEM). The results of X-ray diffraction (XRD), High resolution TEM (HRTEM) and selected area electron diffraction (SAED) indicate that the synthesized Fe3O4 nanoparticles have the inverse cubic spinel structure without the presence of any other phase impurities. The hysteresis loops of the Fe3O4 nanoparticles at room temperature show superparamagnetic behavior and the saturation magnetization of the Fe3O4 samples increases with increasing reaction temperature and time.

  10. HRTEM observation of bonding interface between Ce-TZP/Al2O3 nanocomposite and porcelain.

    PubMed

    Ban, Seiji; Nawa, Masahiro; Sugata, Fumio; Tsuruki, Jiro; Kono, Hiroshi; Kawai, Tatsushi

    2014-01-01

    The surface of a ceria-stabilized tetragonal zirconia polycrystal (Ce-TZP/Al2O3) nanocomposite was sandblasted by alumina particles and veneered with feldspathic porcelain via a conventional condensation method. The part of each specimen containing the interface layer was sliced to ultrathin sections with an argon ion slicer, and these sliced sections were observed using high-resolution transmission electron microscopy (HRTEM). For both interfaces, Ce-TZP/porcelain and Al2O3/porcelain, no transition layers due to abrupt changes in atomic distributions were observed. Besides, the porcelain layers of both interfaces consisted of homogeneous amorphous phases. These results suggested that both Ce-TZP and Al2O3 could be directly bonded to porcelain by Van der Waals forces arising from the close contact between them. PMID:24998172

  11. TEM and HRTEM of Soot-in-oil particles and agglomerates from internal combustion engines

    NASA Astrophysics Data System (ADS)

    Fay, M. W.; La Rocca, A.; Shayler, P. J.

    2014-06-01

    Over time, the performance of lubricating oil in a diesel engine is affected by the build-up of carbon soot produced by the combustion process. TEM and HRTEM are commonly used to investigate the characteristics of individual and agglomerated particles from diesel exhaust, to understand the structure and distribution of the carbon sheets in the primary particles and the nanostructure morphology. However, high resolution imaging of soot-in-oil is more challenging, as mineral oil is a contaminant for the electron microscope and leads to instability under the electron beam. In this work we compare solvent extraction and centrifugation techniques for removing the mineral oil contaminant, and the effect on particle size distribution.

  12. IMAGE-WARP: A real-space restoration method for high-resolution STEM images using quantitative HRTEM analysis

    Microsoft Academic Search

    Aleksander Re?nik; Günter Möbus; Sašo Šturm

    2005-01-01

    We have developed a new method for processing distorted high-resolution scanning transmission electron microscopy (STEM) images. The method is based on finding the displaced vertices in the experimental STEM image and warping to geometrically correct reference grid of the object. As a reference grid for warping a structural model obtained using a high-resolution transmission electron microscopy (HRTEM) analysis of the

  13. Room temperature optical and magnetic properties of polyvinylpyrrolidone capped ZnO nanoparticles

    SciTech Connect

    Chakrabarti, Mahuya, E-mail: mahuya@veccal.ernet.in [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata-700064 (India); Das, S. [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032 (India); Chakrabarti, Keka R.; Sanyal, D.; Chakrabarti, A. [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata-700064 (India)

    2009-09-15

    Defect induced room temperature ferromagnetic properties of polyvinylpyrrolidone (PVP) capped nanocrystalline ZnO samples have been studied. Crystal phase and the lattice parameter of the synthesized nanocrystalline samples have been determined from X-ray diffraction spectra (XRD) and high-resolution transmission electron micrographs (HR-TEM). Room temperature photoluminescence (PL) spectrum for the bare ZnO sample shows a strong band at {approx} 379 nm and another band at {approx} 525 nm. The PL spectra also revealed that the number of oxygen vacancies in the uncapped sample is more than the PVP capped sample. Both sample exhibit ferromagnetic property at room temperature when annealed at 500 deg. C for 3 h, due to the formation of adequate oxygen vacancy related defects. The saturation magnetization for the annealed PVP capped sample is found to be larger compared to that for the uncapped sample.

  14. Synthesis, structure, and magnetic studies on the CoFe2O4-BiFeO3 nanocomposite films with different number of CoFe2O4 layers

    NASA Astrophysics Data System (ADS)

    Liu, Y. Q.; Zhang, B.; Wu, Y. H.; Zhang, J.; Li, D.; Liu, Y.; Wei, M. B.; Yang, J. H.

    2013-09-01

    The multiferroic heterostructures consisting of CoFe2O4 (CFO)-BiFeO3 (BFO) layers with increasing the number of CFO layers (2, 4, 6 and 8) have been grown on LaNiO3 buffered Si (1 0 0) substrate by a simple sol-gel spin-coating route. X-ray diffraction (XRD) shows that the CFO and BFO phases have been successfully retained in the heterostructures and the films are polycrystalline. The high resolution transmission electron microscope (HRTEM) images show the clear interplanar distances and the interface between the two phases. The magnetization (M) versus field (H) loops reveal that, with increasing the CFO layers, the magnetization of CFO-BFO films will be enhanced. The Ms, Mr and Hc of the composite film with 8 CFO layers are measured to be the largest values of 1304 emu/cm3, 562 emu/cm3 and 2074 Oe, respectively.

  15. Ceramic Nano-particle/Substrate Interface Bonding Formation Derived from Dynamic Mechanical Force at Room Temperature: HRTEM Examination

    NASA Astrophysics Data System (ADS)

    Yao, Hai-Long; Yang, Guan-Jun; Fan, Sheng-Qiang; Li, Cheng-Xin; Li, Chang-Jiu

    2015-04-01

    The bonding of TiO2 nano-particle/substrate is a critical factor influencing the performance of dye-sensitized solar cells. In order to reveal the bonding properties at TiO2 nano-particle/substrate interface, high-resolution transmission electron microscopy (HRTEM) analysis was adopted to TiO2 coatings prepared by three different approaches. In the HRTEM analysis, the effective bonding mode is allowed to distinguish from the false image overlapping. Results show that large areas of effective bonding between nano-TiO2 particles and the substrate surface formed in the room temperature cold sprayed coating and mechanically pressed coating, while only limited interface areas with the effective bonding were observed in the coating deposited by non-pressed method. These results confirm that both high impact pressure during the room temperature cold spraying and mechanical pressure contribute to the bonding formation at the particle/substrate interface.

  16. TEM, HRTEM, electron holography and electron tomography studies of gamma' and gamma'' nanoparticles in Inconel 718 superalloy.

    PubMed

    Dubiel, B; Kruk, A; Stepniowska, E; Cempura, G; Geiger, D; Formanek, P; Hernandez, J; Midgley, P; Czyrska-Filemonowicz, A

    2009-11-01

    The aim of the study was the identification of gamma' and gamma'' strengthening precipitates in a commercial nickel-base superalloy Inconel 718 (Ni-19Fe-18Cr-5Nb-3Mo-1Ti-0.5Al-0.04C, wt %) using TEM dark-field, HRTEM, electron holography and electron tomography imaging. To identify gamma' and gamma'' nanoparticles unambiguously, a systematic analysis of experimental and theoretical diffraction patterns were performed. Using HRTEM method it was possible to analyse small areas of precipitates appearance. Electron holography and electron tomography techniques show new possibilities of visualization of gamma' and gamma'' nanoparticles. The analysis by means of different complementary TEM methods showed that gamma'' particles exhibit a shape of thin plates, while gamma' phase precipitates are almost spherical. PMID:19903242

  17. Measurement of Crystallinity and Phase Composition of Hydroxyapatite by XRD

    E-print Network

    calcium phosphates are also present. Impurity phases such as - and -tricalcium phosphate (TCP), even Ca,ArbitraryUnits 2 th e ta , o Figure 2. XRD trace of a calcium phosphate glass simulating amorphous HA. 0 12 00 0 2, amorphous calcium phosphate displays a second band of amorphous scatter (Figure 2, arrowed region

  18. Mössbauer and XRD study of pulse plated Fe P and Fe Ni thin layers

    NASA Astrophysics Data System (ADS)

    Mikó, Annamária; Kuzmann, Ern?; Lakatos-Varsányi, Magda; Kákay, Attila; Nagy, Ferenc; Varga, Lajos Károly

    2005-09-01

    57Fe conversion electron Mössbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe P and Ni Fe coatings. XRD and 57Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm-2) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm-2). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni Fe alloy with a very fine, 5 8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni Fe and Fe P pulse plated thin layers.

  19. Advancements in the characterization of 'hyper-thin' oxynitride gate dielectrics through exit wave reconstruction HRTEM and XPS

    SciTech Connect

    Principe, E.L.; Watson, D.G.; Kisielowski, C.

    2002-09-01

    The physical thickness of silicon oxynitride gate dielectric materials currently in development have dimensions in the range of 15-20 Angstrom ({approx}6-8 oxygen atoms), while approaching the dielectric constant equivalent oxide thickness (EOT) of 12 Angstrom silicon dioxide. These structures present serious challenges in meeting stringent requirements within the semiconductor industry for precise determination of thickness, interfacial roughness and chemical distribution. Limitations in conventional HRTEM must be removed that would minimize errors in such measurements. Our approach was to use the National Center for Electron Microscopy (NCEM) One Angstrom Microscope (O Angstrom M), together with focal series acquisition (FSA) and exit wave reconstruction (EWR) techniques to obtain <0.8A interpretable resolution. HRTEM data on the same oxynitride materials from an aberration corrected (Cs=0) microscope were also collected as part of this work, as were scanning TEM (STEM) measurements. The H RTEM characterization provides an absolute calibration and validation for a precise ''near-line'' metrology to determine gate oxide thickness and nitrogen dose using x-ray photoelectron spectroscopy (XPS).

  20. Structural and magnetic properties of Gd3+ ion substituted magnesium ferrite nanopowders

    NASA Astrophysics Data System (ADS)

    Elkady, Ashraf S.; Hussein, Shaban I.; Rashad, Mohamed M.

    2015-07-01

    Nanocrystalline MgGdxFe2-xO4 powders (where x=0, 0.05, 0.1, 0.2, 0.25, 0.3) have been synthesized by the ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM) were applied in order to study the effect of variation of Gd3+ ion substitution and its impact on crystal structure, crystallite size, lattice parameters, nanostructure and magnetic properties of the formed powders. XRD indicated that, after doping and calcination at 400 °C for 2 h, all samples have two spinel ferrite structures namely cubic and tetragonal phases, which are dependent on Gd3+ ion concentration. The cubic phase is found to increase with increasing the Gd3+ ion molar ratio up to 0.1, compared to pure MgFe2O4 and higher Gd3+ content samples. Indeed, with increasing Gd3+ ion, the crystallite size was almost unchanged whereas the lattice parameter was found to increase. FT-IR spectrum showed broadening of the ?2 band and the presence of another band in the range (465-470 cm-1) upon adding Gd3+ ion, which confirm the presence of Gd3+ ion in addition to Fe3+ ion at octahedral site. Besides, these bands were assigned to the formation of (Gd3+-O2-) complexes at B-sites. HRTEM images showed that the studied samples consist of nanocrystallites having average particle sizes around 9 nm for pure MgFe2O4 up to 27 and 42 nm for the Gd3+ ion substituted MgFe2O4 of molar ratio 0.05 and 0.30, respectively. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Gd concentration incorporation up to x=0.1, as a result of the change of cubic and tetragonal spinel ratio and lattice parameters. Meanwhile, the formed powders exhibited superparamagnetic characteristics. Therefore, such newly synthesized superparamagnetic nanoparticles, containing Gd3+ ion can be considered as a promising candidate for use in several potential applications including neutron capture therapy (NCT), magnetic hyperthermia, ferrofluids and magnetic resonance imaging (MRI).

  1. CXMS and XRD analyses of heat treated A533B stainless steel

    NASA Astrophysics Data System (ADS)

    Morelos-López, E.; Cabral-Prieto, A.; Nava, N.; García-Santibañez, F.; Nosetti, C.

    2014-04-01

    Heat induced surface changes on A533B stainless steel were followed by XRD and CXMS techniques. Whereas the XRD patterns of the studied A533B samples were characteristic of ?-Fe phase only, the surface Mössbauer spectrum showed a broad sextet, being fitted with two magnetic patterns whose hyperfine magnetic fields were 33 and 31 T associated with a pure and perturbed ?-Fe phase, respectively and a broad singlet with an isomer shift ? A533 B = -0.115(4) mms-Fe, characteristic of the ?-Fe phase. This singlet, probably, arising from the samples' surface only was further analyzed by using a singlet and a quadrupole doublet. From hyperfine distribution and discrete value calculations of their corresponding hyperfine parameters, the quadrupole interaction was the most affected by thermal treatments ranging from 300° to 700 °C showing a slight decrease at 600 °C. The average values of the hyperfine parameters were ? 1 = - 0.110(6) mms-Fe for the singlet, and ? 2 = -0.081 (6) mms-Fe and ?2 = 0.143(7) mm/s) for the quadrupole doublet, respectively. In spite of the temperature dependence of the quadrupole splitting on the doublet, which was higher than that of the isomer shifts of both patterns, only a single defect type was suggested, being associated with monovacancias near the 57Fe sites.

  2. Investigation of the Distribution of Fission Products Silver, Palladium and Cadmium in Neutron Irradiated SIC using a Cs Corrected HRTEM

    SciTech Connect

    I. J. van Rooyen; E. Olivier; J. H Neethlin

    2014-10-01

    Electron microscopy examinations of selected coated particles from the first advanced gas reactor experiment (AGR-1) at Idaho National Laboratory (INL) provided important information on fission product distribution and chemical composition. Furthermore, recent research using STEM analysis led to the discovery of Ag at SiC grain boundaries and triple junctions. As these Ag precipitates were nano-sized, high resolution transmission electron microscopy (HRTEM) examination was used to provide more information at the atomic level. This paper describes some of the first HRTEM results obtained by examining a particle from Compact 4-1-1, which was irradiated to an average burnup of 19.26% fissions per initial metal atom (FIMA), a time average, volume-averaged temperature of 1072°C; a time average, peak temperature of 1182°C and an average fast fluence of 4.13 x 1021 n/cm2. Based on gamma analysis, it is estimated that this particle may have released as much as 10% of its available Ag-110m inventory during irradiation. The HRTEM investigation focused on Ag, Pd, Cd and U due to the interest in Ag transport mechanisms and possible correlation with Pd, Ag and U previously found. Additionally, Compact 4-1-1 contains fuel particles fabricated with a different fuel carrier gas composition and lower deposition temperatures for the SiC layer relative to the Baseline fabrication conditions, which are expected to reduce the concentration of SiC defects resulting from uranium dispersion. Pd, Ag, and Cd were found to co-exist in some of the SiC grain boundaries and triple junctions whilst U was found to be present in the micron-sized precipitates as well as separately in selected areas at grain boundaries. This study confirmed the presence of Pd both at inter- and intragranular positions; in the latter case specifically at stacking faults. Small Pd nodules were observed at a distance of about 6.5 micron from the inner PyC/SiC interface.

  3. Integration of TEM/Hrtem onservations and C-isotope geochemistry to characterize organic matter in early Archaean rocks

    NASA Astrophysics Data System (ADS)

    Glikson, M.; Golding, S.; Duck, L.; Webb, R.

    2009-04-01

    TEM was applied to observe and characterize carbonaceous materials (CM) extracted from black cherts in the 'white smoker type' deposit of the ca.3.5Ga (model Pb/Pb ages =3.49-3.51Ga) Dresser ormation, and the overlying black argillites of the 3.46Ga Salgash Subgroup, in the Pilbara of Western Australia. These were characterized by Transmission Electron Microscopy (TEM) coupled with electron dispersive spectral analysis (EDS), High Resolution TEM (HRTEM) to determine molecular ordering, and C-isotope geochemistry. Observations using TEM and HRTEM enabled morphological and fine structure distinctions between the various populations of CM both in the Dresser and Salgash samples. These formed the basis for their interpretations. Organic petrology using reflected light microscopy was applied to whole rock samples to observe mineral-organic relationship and structure relative to host rock texture. These supported insitu, syn-depositional mode for the Dresser Formation CM. Reflectance % (Ro) of CM determined on polished whole rock samples and polished resin-embedded CM concentrates enabled the reconstruction of its thermal history. These yielded several Ro populations in the Dresser Formation samples: probable microbial cells preserved in fluid inclusions within quartz crystals, severely thermally degraded CM possibly originally belonging to microbial cells, CM coating mineral grains and reworked CM particles. On the other hand, the Salgash suite of samples from the Apex Basalt Formation yielded consistent very high Ro values corresponding to graphite stage organic metamorphism. the weak optical anisotropy of the graphite points to a defferent mode of formation than regional metamorphism. Two main graphite forms have been identified, namely a platy and tubular. The tubular form when observed in HRTEM showed nano-tubes and fullerenes. Dresser Formation samples are isotopically light in the range of -32.1 to -38.2per mil supporting a biological source. Although in TEM four distinct types of CM could be identified and characterized, C-isotope analysis was done on mixed CM concentrates where all types were present. Nevertheless, the isotopically lighter samples contained a notable input from the nonm thermally degraded microbial cells entombed within fluid inclusions, liberated during the demineralizing process. On the otther hand the "heavier" samples contained predominantly thermally degraded high Ro CM. C-isotope compositions of the Salgash CM are relatively heavy, prodiminantly between 22.5 and 28.6 per mil consistent with very high thermal stress. Furthermore, the Salgash suite of samples show a C-isotope trend where in the top part of the section the CM becomes "lighter" with depth, down to 143m depth. The latter having the "lightest" values. An inversion of this trend occurs below this depth, where CM becomes increasingly isotopically heavier. The upper part of the section is characterized by platy graphite with rare occurrence of nanotubes observed. Predominantly tubular graphite/nanotubes and fullerenes characterize sample SAL-13 at 142. depth coinciding with the isotopically lightest values. From then downwards CM becomes increasingly "heavier" signifying highest temperatures experienced. Observations in TEM and HRTEM showed an increase in the presence of void-enclosed carbon nano-spheres possibly fullerenes detached from platy graphite, often forming a condensed mess with few recognisable fused tubular structures.

  4. HRTEM and ADF-STEM of precipitates at peak-ageing in cast A356 aluminium alloy

    Microsoft Academic Search

    N. Chomsaeng; M. Haruta; T. Chairuangsri; H. Kurata; S. Isoda; M. Shiojiri

    2010-01-01

    Precipitates at peak-ageing in an A356 Al–Mg–Si alloy cast by a semi-solid process have been studied by high-resolution transmission electron microscopy (HRTEM) and annular dark-field scanning transmission electron microscopy (ADF-STEM). The major precipitate (ppt) at peak-ageing is the monoclinic ?? or pre-??. Its orientation relationship with the fcc-Al matrix is [001]Al\\/\\/[010]ppt, (0?2?0)Al\\/\\/coincide(6?0?1)ppt and (2?0?0)Al\\/\\/coincide(4¯?0?3)ppt, equivalent to [001]Al\\/\\/[010]ppt, (1¯?3?0)Al\\/\\/(1?0?0)ppt and (320)Al\\/\\/(001)ppt.

  5. A Combined XRD/XRF Instrument for Lunar Resource Assessment

    NASA Technical Reports Server (NTRS)

    Vaniman, D. T.; Bish, D. L.; Chipera, S. J.; Blacic, J. D.

    1992-01-01

    Robotic surface missions to the Moon should be capable of measuring mineral as well as chemical abundances in regolith samples. Although much is already known about the lunar regolith, our data are far from comprehensive. Most of the regolith samples returned to Earth for analysis had lost the upper surface, or it was intermixed with deeper regolith. This upper surface is the part of the regolith most recently exposed to the solar wind; as such it will be important to resource assessment. In addition, it may be far easier to mine and process the uppermost few centimeters of regolith over a broad area than to engage in deep excavation of a smaller area. The most direct means of analyzing the regolith surface will be by studies in situ. In addition, the analysis of the impact-origin regolith surfaces, the Fe-rich glasses of mare pyroclastic deposits, are of resource interest, but are inadequately known; none of the extensive surface-exposed pyroclastic deposits of the Moon have been systematically sampled, although we know something about such deposits from the Apollo 17 site. Because of the potential importance of pyroclastic deposits, methods to quantify glass as well as mineral abundances will be important to resource evaluation. Combined x ray diffraction (XRD) and x ray fluorescence (XRF) analysis will address many resource characterization problems on the Moon. XRF methods are valuable for obtaining full major-element abundances with high precision. Such data, collected in parallel with quantitative mineralogy, permit unambiguous determination of both mineral and chemical abundances where concentrations are high enough to be of resource grade. Collection of both XRD and XRF data from a single sample provides simultaneous chemical and mineralogic information. These data can be used to correlate quantitative chemistry and mineralogy as a set of simultaneous linear equations, the solution of which can lead to full characterization of the sample. The use of Rietveld methods for XRD data analysis can provide a powerful tool for quantitative mineralogy and for obtaining crystallographic data on complex minerals.

  6. HRTEM investigations between minerals, fluids and lithobiontic communities during natural weathering. Progress report, September 1, 1993--February 28, 1994

    SciTech Connect

    Banfield, J.F.; Barker, W.W.

    1994-02-01

    HRTEM and AEM analysis of riebeckite and acmite from the interiors of moderately weathered syenite reveals that interaction of these minerals with surficial fluids resulted in the almost complete removal of Na, Ca, and Si. Fe remained relatively immobile, forming arrays of semi-oriented nanocrystalline ferrihydrite and goethite at the primary mineral-secondary mineral interface. The goethite intimately contacts an irregularly corroded amphibole surface. Smectite occurs sporadically as isolated crystallites a few layers thick which are surrounded by goethite. No obvious structural alignment between clay and amphibole or pyroxene was seen. Data suggest that almost all Si is transported in solution to more open regions between islands of nanocrystalline goethite, where it crystallizes as an Fe - rich smectite. Alteration assemblages in wider channels are comprised of euhedral goethite crystals that, within a submicron-sized area, range in size from 5--40 manometers. Sub-grain boundary structures and the porosity distribution suggests evolution of particle size by coarsening. Optical microscopy demonstrates intimate contact between lichen thalli and mineral surfaces. Lichen thalli exploit cracks and open cleavages to extend several millimeters within mineral interiors. Preliminary TEM data suggest the alteration assemblage consists of a polymer-bound mass of chemically complex aluminosilicates.

  7. Synthesis and characterization of poly(divinylbenzene)-coated magnetic iron oxide nanoparticles as precursor for the formation of air-stable carbon-coated iron crystalline nanoparticles.

    PubMed

    Boguslavsky, Yonit; Margel, Shlomo

    2008-01-01

    Maghemite (gamma-Fe2O3) nanoparticles of 15 +/- 3 nm diameter were prepared by nucleation of gelatin/iron oxide followed by growth of gamma-Fe2O3 films onto these nuclei. The gamma-Fe2O3 nanoparticles were coated with polydivinylbenzene (PDVB) by emulsion polymerization of divinylbenzene (DVB) in an aqueous continuous phase containing the gamma-Fe2O3 nanoparticles. The PDVB-coated gamma-Fe2O3 nanoparticles, dispersed in water, were separated from homo-PDVB nanoparticles using the high gradient magnetic field (HGMF) technique. The influence of DVB concentration on the amount of PDVB coating, on the size and size distribution of the coated gamma-Fe2O3 nanoparticles and on their magnetic properties, has been investigated. Air-stable carbon-coated iron (alpha-Fe/C) crystalline nanoparticles of 41 +/- 12 nm diameter have been prepared by annealing the PDVB-coated gamma-Fe2O3 nanoparticles at 1050 degrees C in an inert atmosphere. These nanoparticles exhibit high saturation magnetization value (83 emu g(-1)) and excellent resistance to oxidation. Characterization of the PDVB-coated gamma-Fe2O3 and of the alpha-Fe/C nanoparticles has been accomplished by TEM, HRTEM, DLS, FTIR, XRD, thermal analysis, zeta-potential, and magnetic measurements. PMID:17927999

  8. Effect of crystallization on soft magnetic properties of nanocrystalline Fe80B10Si8Nb1Cu1 alloy

    NASA Astrophysics Data System (ADS)

    Hosseini-Nasb, Farzad; Beitollahi, Ali; Moravvej-Farshi, Mohammad Kazem

    2015-01-01

    The crystallization processes that occur in amorphous melt-spun ribbons of nominal composition Fe80B10Si8Nb1Cu1 during preparation and heat treatment affect the soft magnetic properties of this alloy. Fe80B10Si8Nb1Cu1 alloys are prepared by different quenching rates (wheel speeds of 10, 20 and 40 m/s) and their soft magnetic properties are studied. The XRD data reveal that as the wheel speed increases, the fraction of crystallinity and the Fe-Si grain size both decrease. These data also show that the sample prepared by the wheel speed of 10 m/s exhibits ?-Fe particles on its free surface. The data for the samples prepared by the wheel speed of 20 and 40 m/s are in good agreement with the HRTEM images. VSM measurements show that these nanostructured samples exhibit coercivity in the range of 3-21 A/m and magnetic saturation in the range of 1.55-1.78 T.

  9. Controlled synthesis and magnetic properties of monodispersed ceria nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Sumeet; Srivastava, Manish; Singh, Jay; Layek, Samar; Yashpal, Madhu; Materny, Arnulf; Ojha, Animesh K.

    2015-02-01

    In the present study, monodispersed CeO2 nanoparticles (NPs) of size 8.5 ± 1.0, 11.4 ± 1.0 and 15.4 ± 1.0 nm were synthesized using the sol-gel method. Size-dependent structural, optical and magnetic properties of as-prepared samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscopy (HR-TEM), ultra-violet visible (UV-VIS) spectroscopy, Raman spectroscopy and vibrating sample magnetometer (VSM) measurements. The value of optical band gap is calculated for each particle size. The decrease in the value of optical band gap with increase of particle size may be attributed to the quantum confinement, which causes to produce localized states created by the oxygen vacancies due to the conversion of Ce4+ into Ce3+ at higher calcination temperature. The Raman spectra showed a peak at ˜461 cm-1 for the particle size 8.5 nm, which is attributed to the 1LO phonon mode. The shift in the Raman peak could be due to lattice strain developed due to variation in particle size. Weak ferromagnetism at room temperature is observed for each particle size. The values of saturation magnetization (Ms), coercivity (Hc) and retentivity (Mr) are increased with increase of particle size. The increase of Ms and Mr for larger particle size may be explained by increase of density of oxygen vacancies at higher calcination temperature. The latter causes high concentrations of Ce3+ ions activate more coupling between the individual magnetic moments of the Ce ions, leading to an increase of Ms value with the particle size. Moreover, the oxygen vacancies may also produce magnetic moment by polarizing spins of f electrons of cerium (Ce) ions located around oxygen vacancies, which causes ferromagnetism in pure CeO2 samples.

  10. XRD and XPS characterisation of transition metal silicide thin films

    NASA Astrophysics Data System (ADS)

    Tam, P. L.; Cao, Y.; Nyborg, L.

    2012-02-01

    Binary transition metal silicides based on the systems Ti-Si, Fe-Si, Ni-Si and Cr-Si were fabricated on Si wafers by means of ion-beam co-sputter deposition and subsequent annealing. The crystalline structures of the phases formed were identified from the characteristic patterns acquired by means of X-ray diffraction (XRD) measurements. The phase formation sequences were described by means of the Pretorius' effective heat of formation (EHF) model. For the Ti-Si, Fe-Si and Ni-Si systems, single phase thin films of TiSi2, ?-FeSi2 and NiSi2 were generated as the model predicts, while a mixture of CrSi + CrSi2 phases was obtained for the Cr-Si system. The surface chemical condition of individual specimens was analysed by using X-ray photoelectron spectroscopy (XPS). The chemical shifts of transition metal 2p3/2 peaks from their metallic to silicide states were depicted by means of the Auger parameters and the Wagner plots. The positive chemical shift of 2.0 eV for Ni 2p3/2 peak of NiSi2 is mainly governed by the initial-state effects. For the other silicide specimens, the initial-state and final-state effects may oppose one another with similar impact. Consequently, smaller binding energy shifts of both negative and positive character are noted; a positive binding energy shift of 0.3 eV for the Fe 2p3/2 level was shown for ?-FeSi2 and negative binding energy shifts of 0.1 and 0.3 eV were determined for CrSi + CrSi2 and TiSi2, respectively.

  11. Removal of fluoride from aqueous solution by polypyrrole/Fe3O4 magnetic nanocomposite.

    PubMed

    Bhaumik, Madhumita; Leswifi, Taile Yvonne; Maity, Arjun; Srinivasu, V V; Onyango, Maurice S

    2011-02-15

    Polypyrrole (PPy)/Fe(3)O(4) magnetic nanocomposite as a novel adsorbent was prepared via in-situ polymerization of pyrrole (Py) monomer using FeCl(3) oxidant in aqueous medium in which Fe(3)O(4) nanoparticles were suspended. The adsorbent was characterized by Attenuated Total Reflectance Fourier transform infrared spectroscope (ATR-FTIR), Brunauer-Emmet-Teller (BET) method, field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscope (HR-TEM), X-ray photoelectron spectroscope (XPS) and X-ray diffraction (XRD). Magnetic property of the adsorbent was measured by electron spin resonance (ESR). Subsequently, the ability of the adsorbent to remove fluoride ions from aqueous solution was demonstrated in a batch sorption mode. Results reveal that the adsorption is rapid and that the adsorbent has high affinity for fluoride, which depends on temperature, solution pH and adsorbent dose. From equilibrium modelling, the equilibrium data is well described by Freundlich and Langmuir-Freundlich isotherms while the adsorption kinetics is described by the pseudo-second-order model. Thermodynamic parameters confirm the spontaneity and endothermic nature of the fluoride adsorption. Meanwhile, the fluoride adsorption proceeds by an ion exchange mechanism. PMID:21112695

  12. How isopolyanions self-assemble and condense into a 2D tungsten oxide crystal: HRTEM imaging of atomic arrangement in an intermediate new hexagonal phase

    SciTech Connect

    Chemseddine, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solarenergieforschung SE4, Glienicker Str. 100, 14109 Berlin (Germany)], E-mail: chemseddine@hmi.de; Bloeck, U. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solarenergieforschung SE4, Glienicker Str. 100, 14109 Berlin (Germany)

    2008-10-15

    The structure and structural evolution of tungstic acid solutions, sols and gels are investigated by high-resolution electron microscopy (HRTEM). Acidification of sodium tungstate solutions, through a proton exchange resin, is achieved in a way that ensures homogeneity in size and shape of intermediate polytungstic species. Gelation is shown to involve polycondensation followed by a self-assembling process of polytungstic building blocks leading to sheets with a layered hexagonal structure. Single layers of this new metastable phase are composed of three-, four- and six-membered rings of WO{sub 6} octahedra located in the same plane. This is the first time that a 2D oxide crystal is isolated and observed by direct atomic resolution. Further ageing and structural evolution leading to single sheets of 2D ReO{sub 3}-type structure is directly observed by HRTEM. Based on this atomic level imaging, a model for the formation of the oxide network structure involving a self-assembling process of tritungstic based polymeric chain is proposed. The presence of tritungstic groups and their packing in electrochromic WO{sub 3} films made by different techniques is discussed. - Graphical abstract: From the isopolyanion to the extended bulk tungsten oxide: HRTEM imaging.

  13. Effect of sintering pressure on structure and magnetic properties of Zn0.99Ni0.01O bulk samples synthesized under different pressures

    NASA Astrophysics Data System (ADS)

    Wang, Yongqiang; Yuan, Chaosheng; Su, Lei; Wang, Zheng; Hao, Junhong; Ren, Yufen

    2015-01-01

    A series of Zn0.99Ni0.01O bulk samples were prepared by a coprecipitation method, and then sintered at 600 °C under various pressures from normal pressure(NP) to 3 GPa. The effects of sintering pressure (PS) on the structure, morphology and magnetic properties of the doping samples were investigated in detail. The XRD and HRTEM results reveal that all samples are of single-phase hexagonal structure. Compared with the sample sintered at normal pressure, the lattice parameters a and c of the samples sintered at high pressures (HP) show a sharply decrease. With the increase of sintering pressure, the particle size gradually increases as well as the particles get closer to each other. At 300 K, the sample sintered at normal pressure shows a superparamagnetic-like behavior, while the samples sintered at high pressures display typical ferromagnetic behaviors. The saturation magnetization of the samples sintered at high pressures is three orders of magnitude larger than that of the one sintered at normal pressure. Our results reveal that an appropriate sintering pressure can tune the magnetic properties of Ni-doped ZnO system by changing the lattice parameters, particle size and inter-particle spacing, which may be helpful to the practical applications.

  14. Remote In-Situ Quantitative Mineralogical Analysis Using XRD/XRF

    NASA Technical Reports Server (NTRS)

    Blake, D. F.; Bish, D.; Vaniman, D.; Chipera, S.; Sarrazin, P.; Collins, S. A.; Elliott, S. T.

    2001-01-01

    X-Ray Diffraction (XRD) is the most direct and accurate method for determining mineralogy. The CHEMIN XRD/XRF instrument has shown promising results on a variety of mineral and rock samples. Additional information is contained in the original extended abstract.

  15. Magnetism

    NSDL National Science Digital Library

    University Corporation for Atmospheric Research Windows to the Universe team

    2007-12-12

    This webpage is part of the University Corporation for Atmospheric Research (UCAR) Windows to the Universe program. It describes the nature and configuration of magnetic fields, which are the result of moving electric charges, including how they cause magnetic objects to orient themselves along the direction of the magnetic force points, which are illustrated as lines. Magnetic field lines by convention point outwards at the north magnetic pole and inward at the south magnetic pole. The site features text, scientific illustrations and an animation. Text and vocabulary are selectable for the beginning, intermediate, or advanced reader.

  16. Interface characterization of XUV multilayer reflectors using HRTEM (high-resolution transmission electron microscopy) and x-ray and XUV reflectance

    SciTech Connect

    Windt, D.L.; Hull, R.; Waskiewicz, W.K.; Kortright, J.B.

    1990-07-01

    We have examined the structure of XUV multilayer coatings using high-resolution transmission electron microscopy (HRTEM). Using a variety of techniques, we have measured the interface widths and the interface topography from the digitized TEM images, and have compared these results to x-ray and XUV reflectance measurements. We find that the structural parameters measured from the TEM images and those deduced from reflectance are consistent in light of the probable systematic errors associated with the measurement and interpretation techniques. 14 refs., 12 figs., 1 tab.

  17. CuFe2O4 magnetic heterogeneous nanocatalyst: Low power sonochemical-coprecipitation preparation and applications in synthesis of 4H-chromene-3-carbonitrile scaffolds.

    PubMed

    Rajput, Jaspreet Kaur; Arora, Priya; Kaur, Gagandeep; Kaur, Manpreet

    2015-09-01

    The paper presents the synthesis and catalytic activity of CuFe2O4 nanoparticles. The CuFe2O4 nanoparticles have been prepared by sonochemical route under low power ultrasonic irradiation (UI) and using silent stirring at room temperature only (ST) along with co-precipitation method, without using any additive/capping agent. The synthesized magnetic nanoparticles were successfully used and compared for the synthesis of 4H-chromene-3-carbonitrile derivatives. The CuFe2O4 nanoparticles obtained by sonochemical route exhibit higher catalytic activity because of small size (0.5-5nm), high surface area (214.55m(2)/g), high thermal stability up to 700°C, recyclability and reusability due to its magnetic characteristics than CuFe2O4 nanoparticles obtained by room temperature silent stirring. The synthesized CuFe2O4 nanoparticles were characterized by FT-IR, SEM-EDX, HR-TEM, XRD, TGA/DTA/DTG, BET, VSM techniques. The present method is of great interest due to its salient features such as environmentally compatible, efficient, short reaction time, chemoselectivity, high yield, cheap, moisture insensitive, green and recyclable catalyst which make it sustainable protocol. PMID:25649833

  18. Structure, room-temperature magnetic and optical properties of Mn-doped TiO2 nano powders prepared by the sol—gel process

    NASA Astrophysics Data System (ADS)

    Ding, Peng; Liu, Fa-Min; Zhou, Chuang-Cang; Zhong, Wen-Wu; Zhang, Huan; Cai, Lu-Gang; Zeng, Le-Gui

    2010-11-01

    TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol—gel process, and were annealed at 500 °C and 800 °C in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 °C are of pure anatase and rutile, respectively. The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron (BMP) theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 °C is stronger than that of the sample treated at 800 °C. The UV—VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping.

  19. Mössbauer, TEM/SAED and XRD investigation on waste dumps of the Valea lui Stan gold mines

    NASA Astrophysics Data System (ADS)

    Constantinescu, Serban Grigore; Udubasa, Sorin S.; Udubasa, Gheorghe; Kuncser, Victor; Popescu-Pogrion, Nicoleta; Mercioniu, Ionel; Feder, Marcel

    2012-03-01

    The complementary investigation techniques, Mössbauer spectroscopy, transmission electron microscopy with selected area electron diffraction (TEM/SAED), X-ray diffraction (XRD) have been used to investigate the fate of the Valea lui Stan, Romania, gold-ore nanoscale-minerals during the long time of residence in the waste dumps. The preliminary investigations showed such waste dumps to contain significant amount of metals which cannot be identified by conventional methods. An intense research activity started up in order to evaluate the possibilities to recycle Valea lui Stan waste dumps and to recover metals by chemical or phytoextraction procedures. The waste dumps naturally show different mineral constituents with clay minerals as major phases, observed by XRD-technique. Although the waste dumps materials have whitish-yellowish colours, MÖSSBAUER technique evidences the presence of the finely dispersed iron bearing minerals. The authors are focusing to inspect and analyze Fe-compounds in the samples collected from Valea lui Stan's waste dumps in order to identify the magnetic phases by Mössbauer technique.

  20. XPS and XRD study of crystalline 3C-SiC grown by sublimation method

    Microsoft Academic Search

    R. J Iwanowski; K Fronc; W Paszkowicz; M Heinonen

    1999-01-01

    Preliminary XPS and XRD studies of the 3C-SiC polycrystals (with the grain size of order of 100 ?m) grown by the sublimation method were performed. The XRD data proved a dominant 3C-SiC structure accompanied by an admixture of the residual 6H-SiC phase. The main core-level photoelectron spectra were analysed in detail. In particular, the C 1s level spectrum revealed a

  1. The proposed icy mineralogy package (XRD\\/XRF) for TandEM

    Microsoft Academic Search

    Andrew Dominic Fortes; Ian G. Wood; David P. Dobson; Paul F. Fewster; Athena Coustenis; Jean-Pierre Lebreton

    2008-01-01

    Introduction: Understanding the geology of Titan's crust, and its interaction with the atmosphere, requires determination of the chemistry and mineralogy of surface materials which can only be achieved unambiguously using a combination of X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD). Here we describe an icy mineralogy package (IMP) consisting of a miniaturised XRD\\/XRF instrument designed primarily with Titan (and

  2. Manganese Based Oxidative Technologies For Water/Wastewater Treatment 

    E-print Network

    Desai, Ishan

    2013-08-27

    and structural properties of ferrites. These laboratory prepared catalysts were thoroughly characterized using XRD, SEM, TEM, HR-TEM, and BET. Their magnetic properties have also been studied. These manganese ferrites offer the potential to enhance hydroxyl...

  3. Doping dependent room-temperature ferromagnetism and structural properties of dilute magnetic semiconductor ZnO:Cu 2+ nanorods

    Microsoft Academic Search

    Prashant K. Sharma; Ranu K. Dutta; Avinash C. Pandey

    2009-01-01

    Copper doped ZnO nanoparticles were synthesized by the chemical technique based on the hydrothermal method. The crystallite structure, morphology and size were determined by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) for different doping percentages of Cu2+ (1–10%). TEM\\/SEM images showed formation of uniform nanorods, the aspect ratio of which varied with doping

  4. Synthesis of Mn-doped ZnO diluted magnetic semiconductors in the presence of ethyl acetoacetate under solvothermal conditions

    Microsoft Academic Search

    Chengbin Jing; Yingjing Jiang; Wei Bai; Junhao Chu; Aiyun Liu

    2010-01-01

    Mn-doped ZnO samples with 5%, 20% and 40% nominal Mn concentrations were prepared in the presence of ethyl acetoacetate under solvothermal conditions. UV absorption spectroscopic analysis discloses that chemical modification was achieved by reaction of Zn or Mn precursor with ethyl acetoacetate in ethanol medium. XRD and HRTEM characterizations indicate that ZnMnO3 impurity phase was formed in the 20% and

  5. Magnetically separable Cu2O/chitosan-Fe3O4 nanocomposites: Preparation, characterization and visible-light photocatalytic performance

    NASA Astrophysics Data System (ADS)

    Cao, Chunhua; Xiao, Ling; Chen, Chunhua; Cao, Qihua

    2015-04-01

    A novel magnetically-separable visible-light-induced photocatalyst, Cu2O/chitosan-Fe3O4 nanocomposite (Cu2O/CS-Fe3O4 NC), was prepared via a facile one-step precipitation-reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu2O/CS-Fe3O4 NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV-vis/DRS. The photocatalytic activity of Cu2O/CS-Fe3O4 NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu2O/CS-Fe3O4 NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu2O was wrapped in chitosan matrix embedded with Fe3O4 nanoparticles. The tight combination of magnetic Fe3O4 and semiconductor Cu2O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu2O/CS-Fe3O4 NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B were still above 87% after five reaction cycles, indicating that Cu2O/CS-Fe3O4 NCs had excellent reusability and stability.

  6. The mineralogy and chemistry analyser (MARS-XRD) for the ExoMars 2018 mission

    NASA Astrophysics Data System (ADS)

    Marinangeli, L.; Hutchinson, I. B.; Stevoli, A.; Adami, G.; Ambrosi, R.; Amils, R.; Assis Fernandes, V.; Baliva, A.; Basilevsky, A. T.; Benedix, G.; Bland, P.; Böttger, A. J.; Bridges, J.; Caprarelli, G.; Cressey, G.; Critani, F.; D'Alessandro, N.; Delhez, R.; Domeneghetti, C.; Fernandez-Remolar, D.; Filippone, R.; Fioretti, A. M.; Garcia Ruiz, J. M.; Gilmore, M.; Hansford, G. M.; Iezzi, G.; Ingley, R.; Ivanov, M.; Marseguerra, G.; Moroz, L.; Pelliciari, C.; Petrinca, P.; Piluso, E.; Pompilio, L.; Sykes, J.; Westall, F.

    2011-10-01

    The Mineralogy and Chemistry Analyser (MARSXRD) is a miniaturised X-ray diffraction and fluorescence (XRD/XRF) spectrometer aimed to the mineralogical characterisation of Martian rocks. Simultaneously, MARS-XRD is able to acquire the diffraction pattern for mineralogical phases identification and the X-ray fluorescence spectrum for the chemical species, providing a complete rock characterization. The X-ray diffractometer (XRD) is the routine instrument used in every Earth Science laboratory to provide the mineralogical composition of rocks. XRD produces unequivocal results because it is based on the recognition of the geometrical properties of the crystal lattice. This kind of investigation is an extremely useful tool to define the textural and petro-mineralogical characteristics of the Martian rocks or soils and provide information on the past Martian environment conditions related to life. The analytic range we plan to cover includes all the silicate minerals, from clays or other phyllosilicates characterised by high interplanar lattice distance, to oxide and carbonates or evaporates (mainly sulphates). This rock spectrum is what we expect to be the target for exobiological exploration. These data will be integrated with those obtained by elemental analysis, in order to determine the exact elemental chemistry characterization of rock components. As mineralogy can be unambiguously derived from XRD analysis, it is probably our most powerful tool for distinguishing targets of biologic importance. In summary, the main scientific objectives of the proposed XRD/XRF instrument, Mars-XRD, are: - In situ determination of the mineral paragenesis of rock samples; - The characterization of the origin of rock samples; - Determination of alteration processes; - Understanding the exobiological potential of the samples. The hardware is developed by the Thales Alenia Space Italia with an important contribution of the Univ. of Leicester for the detection system.

  7. Magnetism

    NSDL National Science Digital Library

    David Stern

    This overview of magnetism provides a brief history prior to 1600 and continues with the work of William Gilbert, Hans Christian Oersted, and Andre-Marie Ampere in describing and exploring the magnetosphere and learning the role that electric current plays in producing magnetism. Magnetic field lines are then discussed, citing the work of Michael Faraday. The work of James Clerk Maxwell and Heinrich Hertz is mentioned in a discussion of the relationship of light waves and radio waves as part of the electromagnetic spectrum.

  8. Using simultaneous SHG and XRD capabilities to examine phase transitions of HMX and TATB*

    NASA Astrophysics Data System (ADS)

    Saw, Cheng K.; Zaug, Joseph M.; Farber, Daniel L.

    2001-06-01

    Simultaneous SHG (second harmonic generation) and XRD (x-ray diffraction) capabilities have been developed at SSRL (Stanford Synchrotron Radiation laboratory) to examine the phase behavior of energetic materials, for example, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and TATB (1,3,5-triamino-2,4,6 trinitrobenzene). This unique capability provides information on the evolution at the molecular level (centro and non-centrosymmetric) of material stability, phase transformation or decomposition reactions, which are important to continue refinement of computational predictions of material properties. This presentation will focus on the instrumentation of Simultaneous SHG and XRD capability on beamline 10-2 at SSRL. Initial results suggest that SHG signal intensities increase for HMX and decrease for TATB when small to large volume structural changes occur at 1 bar. We will also present both SHG and XRD results and attempt to correlate time-dependent structural changes of HMX and TATB.

  9. Definitive Mineralogical Analysis of Mars Analog Rocks Using the CheMin XRD/XRF Instrument

    NASA Technical Reports Server (NTRS)

    Blake, D. F.; Sarrazin, P.; Bish, D. L.; Feldman, S.; Chipera, S. J.; Vaniman, D. T.; Collins, S.

    2004-01-01

    Mineral identification is a critical component of Mars Astrobiological missions. Chemical or elemental data alone are not definitive because a single elemental or chemical composition or even a single bonding type can represent a range of substances or mineral assemblages. Minerals are defined as unique structural and compositional phases that occur naturally. There are about 15,000 minerals that have been described on Earth, all uniquely identifiable via diffraction methods. There are likely many minerals yet undiscovered on Earth, and likewise on Mars. If an unknown phase is identified on Mars, it can be fully characterized by structural (X-ray Diffraction, XRD) and elemental analysis (X-ray Fluorescence, XRF) without recourse to other data because XRD relies on the principles of atomic arrangement for its determinations. XRD is the principal means of identification and characterization of minerals on Earth.

  10. Data acquisition and control software for XRD beamline at Indus-2

    SciTech Connect

    Kane, Sanjeev R.; Garg, C. K.; Sinha, A. K. [Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

    2010-06-23

    X-ray diffraction (XRD) beamline is under commissioning on Indus-2 synchrotron radiation facility. The experimental setup of XRD beamline consists of a six-circle diffractometer and various detector systems such as scintillation detector, ionization chamber and image plate. The diffractometer can be controlled via EIA232 serial interface or Ethernet. Standard data acquisition software with a graphical user interface has been developed using LabVIEW. A firm safety and error handling scheme is implemented for failsafe operation of the experimental station. This paper describes in detail the data acquisition and control software for the experimental station.

  11. Cation distribution in copper ferrite nanoparticles of ferrofluids: A synchrotron XRD and EXAFS investigation

    Microsoft Academic Search

    J. A. Gomes; M. H. Sousa; G. J. da Silva; F. A. Tourinho; J. Mestnik-Filho; R. Itri; G. de M. Azevedo; J. Depeyrot

    2006-01-01

    This work reports on the structural characterization of a copper ferrite nanoparticle sample, prepared by coprecipitation method, on both short (EXAFS) and long range (XRD) scales. The diffractograms obtained at room temperature were used for Rietveld refinement to determine the lattice parameters, the oxygen position, the mean size of the nanomaterial and the inversion degree, indicating the existence of a

  12. Microstructure of hard magnetic bccFe\\/NdFeB nanocomposite alloys

    Microsoft Academic Search

    M Yamasaki; M Hamano; H Mizuguchi; T Kobayashi; K Hono; H Yamamoto; A Inoue

    2001-01-01

    The microstructure of amorphous-phase remaining bccFe\\/NdFeB nanocomposite NdvFebalCo8NbxCuyBz (V = 6–8, x = 0–2.5, y = 0–0.5 and z = 6–7 at%) magnet alloys, which were prepared by melt spinning, was investigated by means of high resolution transmission electron microscopy (HR-TEM), three-dimensional atom probing (3DAP), and Mössbauer spectroscopy. It was found by HR-TEM that a small amount of amorphous phase

  13. Investigation of Catastrophic Optical Mirror Damage in High Power Single-Mode InGaAs-AlGaAs Strained Quantum Well Lasers with Focused Ion Beam and HR-TEM Techniques

    Microsoft Academic Search

    Yongkun Sin; Nathan Presser; Brendan Foran; Maribeth Mason; Steven C. Moss

    2007-01-01

    We report our investigation of catastrophic optical mirror damage (COMD) in 980 nm high power single spatial mode InGaAs-AlGaAs strained quantum well (QW) lasers using focused ion beam (FIB) and high-resolution transmission electron microscope (HR-TEM) techniques.

  14. HRTEM and EFTEM Observations of Matrix in the Oxidized CV3 Chondrite ALH 84028: Implications for the Origins of Matrix Olivines

    NASA Technical Reports Server (NTRS)

    Abreu, Neyda M.; Brearley, Adrian J.

    2003-01-01

    The determination of the nature, distribution, and origin of organic material in carbonaceous chondrites is fundamental to understanding early solar nebular conditions and the origin of life. Using a variety of extraction techniques, followed by detailed chemical analysis, an extensive suite of organic compounds has been identified in carbonaceous chondrites. These data have provided key information on the diversity and isotopic composition of the organic component in chondrites. However, one disadvantage of extraction techniques is that all information regarding the spatial distribution of the organics on a fine scale is lost. This is especially important for the insoluble macromolecular carbon, which constitutes approximately 70% of the carbon in carbonaceous chondrites such as Murchison. The distribution and mineralogical associations may provide important constraints on the possible origins of the carbonaceous material. Our previous studies of the CV3 chondrites Allende and Vigarano have demonstrated that energy filtered transmission electron microscopy (EFTEM), combined with high resolution TEM (HRTEM) are powerful tools for the in situ characterization of insoluble organic matter in carbonaceous chondrites. In this study, we have used SEM and TEM techniques to characterize the matrix mineralogy of the CV3 chondrite ALH 84028 and examine the distribution and mineralogical associations of carbon. We are especially interested in establishing whether the occurrence of poorly graphitized carbon (PGC), observed in Allende matrix olivines, is common to all oxidized CV3 chondrites or is a unique feature of Allende.

  15. Effects of different magnetic flux densities on microstructure and magnetic properties of molecular-beam-vapor-deposited nanocrystalline Fe64Ni36 thin films

    NASA Astrophysics Data System (ADS)

    Cao, Yongze; Wang, Qiang; Li, Guojian; Ma, Yonghui; Du, Jiaojiao; He, Jicheng

    2015-04-01

    The nanocrystalline Fe64Ni36 thin films were prepared by molecular-beam-vapor deposition under different magnetic flux densities. The microstructure and magnetic properties of thin films were examined by AFM, TEM, HRTEM and VSM. The results show that with the increase of magnetic flux densities, the changing trend of the average particle size is the same as the coercive force except 6 T. Under 6 T condition, the thin film became the mixture of bcc and fcc phases, which leads to slight increase of the coercive force. In addition, the HRTEM result shows the short-range ordered clusters (embryos) or nucleation rate of thin films increase with increasing magnetic flux densities.

  16. EXAFS and XRD Studies with Subpicometer Accuracy: The Case of ReO3

    SciTech Connect

    Purans, Juris; Dalba, Giuseppe; Fornasini, Paolo [Dipartimento di Fisica, Universita di Trento, I-38050, Povo (Trento) (Italy); Kuzmin, Alexei [Institute of Solid State Physics, University of Latvia, LV-1063 Riga (Latvia); De Panfilis, Simone [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France); Rocca, Francesco [Istituto di Fotonica e Nanotecnologie del CNR, I-38050, Povo (Trento) (Italy)

    2007-02-02

    EXAFS has been measured on ReO3 from 30 to 600 K; XRD has been contemporarily measured above 300 K. In this way, it has been possible to compare the expansion of the lattice parameter (XRD) and of the bond lengths (EXAFS), measured at the same time. EXAFS was interpreted by the cumulant approach, using ReO3 measured at low temperature as reference. According to our results, ReO3 shows a complicated behavior of thermal expansion: (i) ultra low or negative expansion below 100 K, (ii) moderate positive expansion above 150 K up to 500 K, (iii) negative expansion from 500K. up to the decomposition temperature. The EXAFS parallel and perpendicular MSRD (mean square relative displacements) have been calculated for the 1st and 4th shells. An unexpected result is that the perpendicular MSRD of the first coordination shell has a weak temperature dependence.

  17. Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation

    SciTech Connect

    Hardy, John S.; Templeton, Jared W.; Edwards, Danny J.; Lu, Zigui; Stevenson, Jeffry W.

    2012-01-03

    A new capability has been developed for analyzing solid oxide fuel cells (SOFCs). This paper describes the initial results of in-situ x-ray diffraction (XRD) of the cathode on an operating anode-supported solid oxide fuel cell. It has been demonstrated that XRD measurements of the cathode can be performed simultaneously with electrochemical measurements of cell performance or electrochemical impedance spectroscopy (EIS). While improvements to the technique are still to be made, the XRD pattern of a lanthanum strontium cobalt ferrite (LSCF) cathode with the composition La0.6Sr0.4Co0.2Fe0.8O3-? (LSCF-6428) was found to continually but gradually change over the course of more than 60 hours of operation in air under typical SOFC operating conditions. It was determined that the most significant change was a gradual increase in the cubic lattice parameters of the LSCF from 3.92502 Å (as determined from the integration of the first 20 hours of XRD patterns) to 3.92650 Å (from the integration of the last 20 hours). This analysis also revealed that there were several peaks from unidentified minor phases that increased in intensity over this timeframe. After a temporary loss of airflow early in the test, the cell generated between 225 and 250 mW/cm2 for the remainder of the test. A large low frequency arc in the impedance spectra suggests the cell performance was gas diffusion limited and that there is room for improvement in air delivery to the cell.

  18. XRD and SEM studies of reactively deposited tin oxide thin films

    Microsoft Academic Search

    Johny T Abraham; Peter Koshy; V K Vaidyan; P S Mukherjee; P Guruswamy; L Prasanna Kumari

    1995-01-01

    Stoichiometric polycrystalline tin oxide thin films were deposited by the reactive evaporation of tin and the SnO2 formation was found to be strongly dependent on the deposition parameters. The preferred orientation of the SnO2 films deposited on different substrates was varying due to the dislocation defects arising during the thin film formation.\\u000a The X-ray diffraction (XRD) studies identified a tetragonal

  19. Comparative XRD analysis ettringite originating from pozzolan and from portland cement

    Microsoft Academic Search

    Rafael Talero

    1996-01-01

    The ettringite is often formed when concrete is attacked by sulphatic waters. In this investigation, a semi-quantitative analysis and study of the ettringite (2? = 9.08 °) in the solid phase of the Fratini test was made by XRD. The cements P-1 (14.11% C3A) P-31 (7.6% C3A) and PY-6 (0.00% C3A), five pozzolans, D,O,A,C and M and five mixed cements

  20. Mineralogical composition of the meteorite El Pozo (Mexico): a Raman, infrared and XRD study.

    PubMed

    Ostrooumov, Mikhail; Hernández-Bernal, Maria del Sol

    2011-12-01

    The Raman (RMP), infrared (IR) and XRD analysis have been applied to the examination of mineralogical composition of El Pozo meteorite (an ordinary chondrite L5 type; village Valle of Allende, founded in State of Chihuahua, Mexico: 26°56'N and 105°24'W, 1998). RMP measurements in the range of 100-3500 cm(-1) revealed principal characteristic bands of the major minerals: olivine, two polymorph modifications of pyroxene (OPx and CPx) and plagioclase. Some bands of the minor minerals (hematite and goethite) were also identified. All these minerals were clearly distinguished using IR and XRD techniques. XRD technique has shown the presence of some metallic phases such as kamacite and taenite as well as troilite and chromite. These minerals do not have characteristic Raman spectra because Fe-Ni metals have no active modes for Raman spectroscopy and troilite is a weak Raman scatterer. Raman mapping microspectroscopy was a key part in the investigation of El Pozo meteorite's spatial distribution of the main minerals because these samples are structurally and chemically complex and heterogeneous. The mineral mapping by Raman spectroscopy has provided information for a certain spatial region on which a spatial distribution coexists of the three typical mineral assemblages: olivine; olivine+orthopyroxene; and orthopyroxene. PMID:21930423

  1. [Study on the vibrational spectra and XRD characters of Huanglong jade from Longling County, Yunnan Province].

    PubMed

    Pei, Jing-cheng; Fan, Lu-wei; Xie, Hao

    2014-12-01

    Based on the conventional test methods, the infrared absorption spectrum, Raman spectrum and X-ray diffraction (XRD) were employed to study the characters of the vibration spectrum and mineral composition of Huanglong jade. The testing results show that Huanglong jade shows typical vibrational spectrum characteristics of quartziferous jade. The main infrared absorption bands at 1162, 1076, 800, 779, 691, 530 and 466 cm(-1) were induced by the asymmetric stretching vibration, symmetrical stretching vibration and bending vibration of Si-O-Si separately. Especially the absorption band near 800 cm(-1) is split, which indicates that Huanglong jade has good crystallinity. In Raman spectrum, the main strong vibration bands at 463 and 355 cm(-1) were attributed to bending vibration of Si-O-Si. XRD test confirmed that Quartz is main mineral composition of Huanglong jade and there is a small amount of hematite in red color samples which induced the red color of Huanglong jade. This is the first report on the infrared, Raman and XRD spectra feature of Huanglong jade. It will provide a scientific basis for the identification, naming and other research for huanglong jade. PMID:25881449

  2. Matching 4.7-Å XRD spacing in amelogenin nanoribbons and enamel matrix.

    PubMed

    Sanii, B; Martinez-Avila, O; Simpliciano, C; Zuckermann, R N; Habelitz, S

    2014-09-01

    The recent discovery of conditions that induce nanoribbon structures of amelogenin protein in vitro raises questions about their role in enamel formation. Nanoribbons of recombinant human full-length amelogenin (rH174) are about 17 nm wide and self-align into parallel bundles; thus, they could act as templates for crystallization of nanofibrous apatite comprising dental enamel. Here we analyzed the secondary structures of nanoribbon amelogenin by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and tested if the structural motif matches previous data on the organic matrix of enamel. XRD analysis showed that a peak corresponding to 4.7 Å is present in nanoribbons of amelogenin. In addition, FTIR analysis showed that amelogenin in the form of nanoribbons was comprised of ?-sheets by up to 75%, while amelogenin nanospheres had predominantly random-coil structure. The observation of a 4.7-Å XRD spacing confirms the presence of ?-sheets and illustrates structural parallels between the in vitro assemblies and structural motifs in developing enamel. PMID:25048248

  3. Copper(0) nanoparticles supported on silica-coated cobalt ferrite magnetic particles: cost effective catalyst in the hydrolysis of ammonia-borane with an exceptional reusability performance.

    PubMed

    Kaya, Murat; Zahmakiran, Mehmet; Ozkar, Saim; Volkan, Mürvet

    2012-08-01

    Herein we report the development of a new and cost-effective nanocomposite catalyst for the hydrolysis of ammonia-borane (NH(3)BH(3)), which is considered to be one of the most promising solid hydrogen carriers because of its high gravimetric hydrogen storage capacity (19.6% wt) and low molecular weight. The new catalyst system consisting of copper nanoparticles supported on magnetic SiO(2)/CoFe(2)O(4) particles was reproducibly prepared by wet-impregnation of Cu(II) ions on SiO(2)/CoFe(2)O(4) followed by in situ reduction of the Cu(II) ions on the surface of magnetic support during the hydrolysis of NH(3)BH(3) and characterized by ICP-MS, XRD, XPS, TEM, HR-TEM and N(2) adsorption-desorption technique. Copper nanoparticles supported on silica coated cobalt(II) ferrite SiO(2)/CoFe(2)O(4) (CuNPs@SCF) act as highly active catalyst in the hydrolysis of ammonia-borane, providing an initial turnover frequency of TOF = 2400 h(-1) at room temperature, which is not only higher than all the non-noble metal catalysts but also higher than the majority of the noble metal based homogeneous and heterogeneous catalysts employed in the same reaction. More importantly, they were easily recovered by using a permanent magnet in the reactor wall and reused for up to 10 recycles without losing their inherent catalytic activity significantly, which demonstrates the exceptional reusability of the CuNPs@SCF catalyst. PMID:22856878

  4. Synthesis and characterization of low-OH?fluor-chlorapatite: A single-crystal XRD and NMR spectroscopic study

    SciTech Connect

    McCubbin, Francis M.; Mason, Harris E.; Park, Hyunsoo; Phillips, Brian L.; Parise, John B.; Nekvasil, Hanna; Lindsley, Donald H. (SBU)

    2008-12-12

    Los-OH apatite of the compositional range Ca{sub 4.99-5.06}(PO{sub 4}){sub 2.98-3.00}F{sub 0.51-0.48}Cl{sub 0.38-0.36}OH{sub 0.14-0.12} was synthesized and characterized structurally by synchrotron-based single-crystal X-ray diffraction (XRD), and multiple nuclear magnetic resonance (NMR) spectroscopic techniques. the average structure is hexagonal with space group P6{sub 3}/m. The presence of scattering in the single-crystal diffraction data set, which is incommensurate within the average hexagonal structure, suggests the presence of localized short-range monoclinic domains. Complex lineshapes in the {sup 31}P and {sup 19}F MAS NMR spectra are also consistent with the presence of an incommensurate phase. No evidence was detected for splitting of the Ca2 site into two distinct sites (as had been previously reported for hexagonal ternary apatities). Structure refinement and {sup 19}F{l_brace}{sup 35}Cl{r_brace} TRAPDOR NMR experiments verified intercolumnal neighboring of F and Cl atoms (inter-column distance of 2.62 {angstrom}) within this low-OH{sup -} apatite suggesting that long-range neighboring of F and Cl within the apatite anion channels is feasible.

  5. The XRD Amorphous Component in John Klein Drill Fines at Yellowknife Bay, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Ming,, Douglas W.; Blake, David; Vaniman, David; Bish, David L; Chipera, Steve; Downs, Robert; Morrison, Shaunna; Gellert, Ralf; Campbell, Iain; Treiman, Alan H.; Achilles, Cherie; Bristow, Thomas; Crisp, Joy A.; McAdam, Amy; Archer, Paul Douglas; Sutter, Brad; Rampe, Elizabeth B.

    2013-01-01

    Drill fines of mudstone (targets John Klein and Cumberland) from the Sheepbed unit at Yel-lowknife Bay were analyzed by MSL payload elements including the Chemistry and Mineralogy (CheMin), APXS (Alpha Particle X-Ray Spectrometer), and Sample Analysis at Mars (SAM) instruments. CheMin XRD results show a variety of crystalline phases including feldspar, pyroxene, olivine, oxides, oxyhydroxides, sulfates, sulfides, a tri-octahedral smectite, and XRD amorphous material. The drill fines are distinctly different from corresponding analyses of the global soil (target Rocknest) in that the mudstone samples contained detectable phyllosilicate. Here we focus on John Klein and combine CheMin and APXS data to calculate the chemical composition and concentration of the amorphous component. The chemical composition of the amorphous plus smectite component for John Klein was calculated by subtracting the abundance-weighted chemical composition of the individual XRD crystalline components from the bulk composition of John Kline as measured by APXS. The chemical composition of individual crystalline components was determined either by stoichiometry (e.g., hematite and magnetite) or from their unit cell parameters (e.g., feldspar, olivine, and pyroxene). The chemical composition of the amorphous + smectite component (approx 71 wt.% of bulk sample) and bulk chemical composition are similar. In order to calculate the chemical composition of the amorphous component, a chemical composition for the tri-octahedral smectite must be assumed. We selected two tri-octahedral smectites with very different MgO/(FeO + Fe2O3) ratios (34 and 1.3 for SapCa1 and Griffithite, respectively). Relative to bulk sample, the concentration of amorphous and smectite components are 40 and 29 wt.% for SapCa1 and 33 and 36 wt.% for Griffithite. The amount of smectite was calculated by requiring the MgO concentration to be approx 0 wt.% in the amorphous component. Griffithite is the preferred smectite because the position of its 021 diffraction peak is similar to that reported for John Klein. In both cases, the amorphous component has low SiO2 and MgO and high FeO + Fe2O3, P2O5, and SO3 concentrations relative to bulk sample. The chemical composition of the bulk drill fines and XRD crystalline, smectite, and amorphous components implies alteration of an initially basaltic material under near neutral conditions (not acid sulfate), with the sulfate incorporated later as veins of CaSO4 injected into the mudstone.

  6. The XRD Amorphous Component in John Klein Drill Fines at Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Morris, R. V.; Ming, D. W.; Blake, D.; Vaniman, D.; Bish, D. L.; Chipera, S.; Downs, R.; Morrison, S.; Gellert, R.; Campbell, I.; Treiman, A. H.; Achilles, C.; Bristow, T.; Crisp, J. A.; McAdam, A.; Archer, P. D.; Sutter, B.; Rampe, E. B.; Team, M.

    2013-12-01

    Drill fines of mudstone (targets John Klein and Cumberland) from the Sheepbed unit at Yel-lowknife Bay were analyzed by MSL payload elements including the Chemistry and Mineralogy (CheMin), APXS (Alpha Particle X-Ray Spectrometer), and Sample Analysis at Mars (SAM) instruments. CheMin XRD results show a variety of crystalline phases including feldspar, pyrox-ene, olivine, oxides, oxyhydroxides, sulfates, sulfides, a tri-octahedral smectite, and XRD amorphous material. The drill fines are distinctly different from corresponding analyses of the global soil (target Rocknest) in that the mudstone samples contained detectable phyllosilicate. Here we focus on John Klein and combine CheMin and APXS data to calculate the chemical composition and concentration of the amorphous component. The chemical composition of the amorphous plus smectite component for John Klein was cal-culated by subtracting the abundance-weighted chemical composition of the individual XRD crystalline components from the bulk composition of John Kline as measured by APXS. The chemical composition of individual crystalline components was determined either by stoichiome-try (e.g., hematite and magnetite) or from their unit cell parameters (e.g., feldspar, olivine, and pyroxene). The chemical composition of the amorphous + smectite component (~71 wt.% of bulk sample) and bulk chemical compositon are similar. In order to calculate the chemical composition of the amorphous component, a chemical composition for the tri-octahedral smectite must be assumed. We selected two tri-octahedral smectites with very different MgO/(FeO + Fe2O3) ratios (34 and 1.3 for SapCa1 and Griffithite, respectively). Relative to bulk sample, the concentration of amorphous and smectite components are 40 and 29 wt.% for SapCa1 and 33 and 36 wt.% for Griffithite. The amount of smectite was calculated by requiring the MgO concentration to be~0 wt.% in the amporphous component. Griffithite is the preferred smectite because the position of its 02l diffraction peak is similar to that reported for John Klein. In both cases, the amorphous component has low SiO2 and MgO and high FeO + Fe2O3, P2O5, and SO3 concentrations relative to bulk sample. The chemical composition of the bulk drill fines and XRD crystalline, smectite, and amorphous components implies alteration of an initially basaltic material under near neutral conditions (not acid sulfate), with the sulfate incorporated later as veins of CaSO4 injected into the mudstone.

  7. Using simultaneous SHG and XRD capabilities to examine phase transitions of HMX and TATB

    Microsoft Academic Search

    Cheng K. Saw; Joseph M. Zaug; Daniel L. Farber; C Ruddle

    2001-01-01

    Simultaneous SHG (second harmonic generation) and XRD (x-ray diffraction) capabilities have been developed at SSRL (Stanford Synchrotron Radiation laboratory) to examine the phase behavior of energetic materials, for example, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and TATB (1,3,5-triamino-2,4,6 trinitrobenzene). This unique capability provides information on the evolution at the molecular level (centro and non-centrosymmetric) of material stability, phase transformation or decomposition reactions, which are

  8. IN-SITU XRD OF OPERATING LSFC CATHODES: DEVELOPMENT OF A NEW ANALYTICAL CAPABILITY

    SciTech Connect

    Hardy, John S.; Templeton, Jared W.; Stevenson, Jeffry W.

    2012-11-19

    A solid oxide fuel cell (SOFC) research capability has been developed that facilitates measuring the electrochemical performance of an operating SOFC while simultaneously performing x-ray diffraction on its cathode. The evolution of this research tool’s development is discussed together with a description of the instrumentation used for in-situ x-ray diffraction (XRD) measurements of operating SOFC cathodes. The challenges that were overcome in the process of developing this capability, which included seals and cathode current collectors, are described together with the solutions that are presently being applied to mitigate them.

  9. Analytical electron microscopy of Mg-SiO smokes - A comparison with infrared and XRD studies

    NASA Technical Reports Server (NTRS)

    Rietmeijer, F. J. M.; Nuth, J. A.; Mackinnon, I. D. R.

    1986-01-01

    Analytical electron microscopy conducted for Mg-SiO smokes (experimentally obtained from samples previously characterized by IR spectroscopy) indicates that the microcrystallinity content of unannealed smokes increases with increased annealing for up to 30 hr. The growth of forsterite microcrystallites in the initially nonstoichiometric smokes may give rise to the contemporaneous growth of the SiO polymorph tridymite and MgO; after 4 hr of annealing, these react to form enstatite. It is suggested that XRD analysis and IR spectroscopy should be conducted in conjunction with detailed analytical electron microscopy for the detection of emerging crystallinity in vapor-phase condensates.

  10. XRD, lead equivalent and UV-VIS properties study of Ce and Pr lead silicate glasses

    SciTech Connect

    Alias, Nor Hayati, E-mail: norhayati@nuclearmalaysia.gov.my; Abdullah, Wan Shafie Wan, E-mail: norhayati@nuclearmalaysia.gov.my; Isa, Norriza Mohd, E-mail: norhayati@nuclearmalaysia.gov.my; Isa, Muhammad Jamal Md, E-mail: norhayati@nuclearmalaysia.gov.my; Zali, Nurazila Mat; Abdullah, Nuhaslinda Ee [Malaysian Nuclear Agency, 43000, Bangi, Kajang, Selangor (Malaysia); Muhammad, Azali [Malaysian Society for Non-Destructive Testing (Malaysia)

    2014-02-12

    In this work, Cerium (Ce) and Praseodymium (Pr) containing lead silicate glasses were produced with 2 different molar ratios low (0.2 wt%) and high (0.4wt%). These types of glasses can satisfy the characteristics required for radiation shielding glasses and minimize the lead composition in glass. The radiation shielding properties of the synthesized glasses is explained in the form of lead equivalent study. The XRD diffraction and UV-VIS analysis were performed to observe the structural changes of the synthesis glasses at 1.5 Gy gamma radiation exposures.

  11. Using Simultaneous SHG and XRD Capabilities to Examine Phase Transitions of HMX and TATB

    SciTech Connect

    Saw, C K; Zaug, J; Farber, D; Ruddle, C

    2001-06-19

    Simultaneous SHG (second harmonic generation) and XRD (x-ray diffraction) capabilities have been developed at SSRL (Stanford Synchrotron Radiation laboratory) to examine the phase behavior of energetic materials, for example, HMX (octahydro- 1,3,5,7-tetranitro- 1,3,5,7-tetrmcine) and TATB (1,3,5-triamino-2,4,6 trinitrobenzene). This unique capability provides information on the evolution at the molecular level (centro and non-centrosymmetric) on material stability, phase transformation or decomposition reactions, which are important to continue refinement of computational predictions of material properties. This paper reports x-ray diffraction experiments on both HMX and TATB with increasing temperature and on simultaneous SHG and XRD experiments at fixed temperature. Our results indicate that, for HMX, the {beta} to {delta} transformation occurs over a range of temperature which do not correlate to the previously reported fast rise in SHG signal close to 17OOC as a phase transformation. No phase transition is observed for TATB, even though, previous paper shows an increase in the SHG signal.

  12. Trace elemental analysis of Indian natural moonstone gems by PIXE and XRD techniques.

    PubMed

    Venkateswara Rao, R; Venkateswarulu, P; Kasipathi, C; Sivajyothi, S

    2013-12-01

    A selected number of Indian Eastern Ghats natural moonstone gems were studied with a powerful nuclear analytical and non-destructive Proton Induced X-ray Emission (PIXE) technique. Thirteen elements, including V, Co, Ni, Zn, Ga, Ba and Pb, were identified in these moonstones and may be useful in interpreting the various geochemical conditions and the probable cause of their inceptions in the moonstone gemstone matrix. Furthermore, preliminary XRD studies of different moonstone patterns were performed. The PIXE technique is a powerful method for quickly determining the elemental concentration of a substance. A 3MeV proton beam was employed to excite the samples. The chemical constituents of moonstones from parts of the Eastern Ghats geological formations of Andhra Pradesh, India were determined, and gemological studies were performed on those gems. The crystal structure and the lattice parameters of the moonstones were estimated using X-Ray Diffraction studies, trace and minor elements were determined using the PIXE technique, and major compositional elements were confirmed by XRD. In the present work, the usefulness and versatility of the PIXE technique for research in geo-scientific methodology is established. PMID:24055999

  13. Characterization of ternary and quaternary zirconias by XRD and EXAFS: result comparison and data modeling

    NASA Astrophysics Data System (ADS)

    Degueldre, C.; Conradson, S.

    2001-10-01

    X-ray diffraction (XRD) data and extended X-ray absorption fine-structure spectroscopy (EXAFS) data are compared for a zirconia-based solid solution such as ternary Er0.05Y0.10Zr0.85O1.925 (inert matrix) and quaternary Er0.05Y0.10Ce0.10Zr0.75O1.925 (simulated inert matrix fuel where Ce is used instead of Pu). Average distances between the ions: metal-oxygen and metal-metal (for the 8 first shells of the cations) obtained by EXAFS are compared with values derived from the lattice parameter gained by XRD using a crystallographic formula derived for the fluorite-type solid solution. Data agreement makes comparison between atomic and crystallographic features very valuable for the characterization of these zirconia-based solid solutions (inert matrix fuel). The effect of the cation size of the dopants on the expansion of the crystallographic lattice is modeled and formal quantification of the lattice-parameter expansion as a function of ceria addition is derived.

  14. XRD and FTIR structural investigation of gadolinium-zinc-borate glass ceramics

    SciTech Connect

    Borodi, G. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)] [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Pascuta, P.; Dan, V.; Pop, V. [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania)] [Technical University, 28 Memorandumului, 400114 Cluj-Napoca (Romania); Stefan, R. [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania)] [Agricultural Science and Veterinary Medicine University, 3-5 Calea Manastur, 400372 Cluj-Napoca (Romania); Radulescu, D. [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)] [University of Medicine and Pharmacy Iuliu Hatieganu, 8 Victor Babes, 400012 Cluj-Napoca (Romania)

    2013-11-13

    X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the (Gd{sub 2}O{sub 3}){sub x}?(B{sub 2}O{sub 3}){sub (60?x)}?(ZnO){sub 40} glass ceramics system, with 0 ? x ? 15 mol%. After heat treatment applied at 860 °C for 2 h, some structural changes were observed and new crystalline phases appeared in the structure of the samples. In these glass ceramics four crystalline phases were identified using powder diffraction files (PDF 2), namely ZnB{sub 4}O{sub 7}, Zn{sub 4}O(B{sub 6}O{sub 12}), Zn{sub 3}(BO{sub 3}){sub 2} and GdBO{sub 3}. From the XRD data, the average unit-cell parameter and the quantitative ratio of the crystallographic phases in the studied samples were evaluated. FTIR data revealed that the BO{sub 3}, BO{sub 4} and ZnO{sub 4} are the main structural units of these glass ceramics network. The compositional dependence of the different structural units which appear in the studied samples was followed.

  15. XRD and EPR structural investigation of some zinc borate glasses doped with iron ions

    NASA Astrophysics Data System (ADS)

    Stefan, Razvan; Pascuta, Petru; Popa, Adriana; Raita, Oana; Indrea, Emil; Culea, Eugen

    2012-02-01

    Glasses in the system xFe2O3·(100-x) [45ZnO·55B2O3] (0?x?10 mol%) have been prepared by melting at 1200 °C and rapidly cooling at room temperature. The obtained samples were submitted to an additional thermal treatment at 570 °C for 12 h in order to relax the glass structure as well as to improve the local order. The as cast and heat treated samples were investigated using X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) measurements. The XRD patterns of all the studied samples show their vitreous nature. Structural modifications occurring in the heat treated samples compared to the untreated ones have been pointed out. EPR spectra of untreated and heat treated samples revealed resonance absorptions centered at g?2.0, g?4.3 and g?6.4. The compositional variation of the line intensity and linewidth of the absorptions from g?4.3 and g?2.0 have been interpreted in terms of the variation in the concentration of the Fe3+ ions and the interaction between the iron ions. The EPR spectra of the untreated samples containing 5 mol% Fe2O3 have been studied at different temperatures (110-290 K). The line intensity of the resonance signals decreases with increase in temperature whereas the linewidth is found to be independent of temperature. It was also found that the temperature variation of reciprocal line intensity obeys the Boltzmann law.

  16. XRD and FTIR structural investigation of gadolinium-zinc-borate glass ceramics

    NASA Astrophysics Data System (ADS)

    Borodi, G.; Pascuta, P.; Stefan, R.; Dan, V.; Pop, V.; Radulescu, D.

    2013-11-01

    X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy measurements have been employed to investigate the (Gd2O3)x?(B2O3)(60-x)?(ZnO)40 glass ceramics system, with 0 ? x ? 15 mol%. After heat treatment applied at 860 °C for 2 h, some structural changes were observed and new crystalline phases appeared in the structure of the samples. In these glass ceramics four crystalline phases were identified using powder diffraction files (PDF 2), namely ZnB4O7, Zn4O(B6O12), Zn3(BO3)2 and GdBO3. From the XRD data, the average unit-cell parameter and the quantitative ratio of the crystallographic phases in the studied samples were evaluated. FTIR data revealed that the BO3, BO4 and ZnO4 are the main structural units of these glass ceramics network. The compositional dependence of the different structural units which appear in the studied samples was followed.

  17. The use of micro-XRD for the study of glaze color decorations

    NASA Astrophysics Data System (ADS)

    Pradell, T.; Molina, G.; Molera, J.; Pla, J.; Labrador, A.

    2013-04-01

    The compounds responsible for the colors and decorations in glass and glazed ceramics include: coloring agents (transition-metal ions), pigments (micro- and nanoprecipitates of compounds that either do not dissolve or recrystallize in the glassy matrix) and opacifiers (microcrystalline compounds with high light scattering capability). Their composition, structure and range of stability are highly dependent not only on the composition but also on the procedures followed to obtain them. Chemical composition of the colorants and crystallites may be obtained by means of SEM-EDX and WDX. Synchrotron radiation micro-X-ray diffraction (SR-micro-XRD) has a small beam size adequate (10 to 50 microns footprint size) to obtain the structural information of crystalline compounds and high brilliance, optimal for determining the crystallites even when present in low amounts. In addition, in glass decorations the crystallites often appear forming thin layers (from 10 to 100 micrometers thick) and they show a depth-dependent composition and crystal structure. Their nature and distribution across the glass/glaze decorations gives direct information on the technology of production and stability and may be related to the color and appearance. A selection of glass and glaze coloring agents and decorations are studied by means of SR-micro-XRD and SEM-EDX including: manganese brown, antimony yellow, red copper lusters and cobalt blue. The selection includes Medieval (Islamic, and Hispano Moresque) and Renaissance tin-glazed ceramics from the 10th to the 17th century AD.

  18. The high - low-p clinoenstatite transition: in situ xrd and ultrasonic study

    NASA Astrophysics Data System (ADS)

    Müller, H. J.; Wunder, B.; Lathe, C.; Schilling, F. R.

    2003-04-01

    Using single-crystal X-ray diffraction analyses in a diamond anvil cell Angel et al. (1992) published the transformation of MgSiO_3 from LCEn to a C2/c-polymorph (HCEn) at around 5.5 - 8.0 GPa and room-T (RT)conditions. This LCEn - HCEn-transition is not quenchable. However, the knowledge of the exact phase boundary positions for the MgSiO_3-transitions is essential as pyroxene is an important component of the Earth's mantle and will significantly influence elastic properties (e.g. v_p, v_s) of the mantle. We determined the HCEn - LCEn-transition by in-situ XRD experiments under high P, T using the multi-anvil appar atus MAX80 at the synchrotron facility HASYLAB, Hamburg. Our preliminary results only represent the minimum P-conditions of the HCEn - LCEn phase boundary, which is approximated by equation P (GPa) = 0.0021T (/C) + 6.06. Nevertheless, our results are in good agreement to data published by Angel & Hugh-Jones (1994). The invariant point defined by the intersection of the HCEn - LCEn equilibrium determined within this study and the OEn - LCEn reaction after Angel &Hugh-Jones (1994) lies at about 7.9 GPa and 875/C. This is in contrast to earlier experimental results of Kanzaki (1991) and Ulmer &Stalder (2001). The samples for the ultrasonic interferometry experiments were prepared by hot-isostatic pressing also using the MAX80. Adjacent XRD ruled out any phase transition during the hip-process. For the ultrasonic measurements one of the six anvils of MAX80 were exchanged by an anvil equipped with lithium niobate p- and s-wave transducers of 33.3 MHz natural frequency (Mueller et al., 2002). Corresponding to the XRD experiments HCEn was formed by increasing the pressure at RT. The velocities of elastic compressional and shear waves were measured under in situ conditions using the classical digital sweep technique. After the phase transition to LCEn as a result of rising the temperature at given pressure the measurements were repeated. The newly developed ultra sonic data transfer function (UDTF) technique, first described by Li (pers. comm.), enabling much faster measurements than the classical method, was used to measure both the elastic wave velocities of LCEn in dependence on pressure at 700/C. To compare the results v_p and v_s were measured at 6.7 GPa and 7.5 GPa using both interferometric techniques. The results demonstrate the correspondence in the limits of less than 1 %.

  19. XRD, SEM, EPR and microwave investigations of ferrofluid-PVA composite films

    Microsoft Academic Search

    R. P. Pant; R. M. Krishna; P. S. Negi; K. Ravat; D. K. Suri; S. K. Gupta; U. Dhawan

    1995-01-01

    Ferrofluid-polymer composite films, prepared under the influence of a magnetic field and without magnetic field, have been studied for their physical characteristics. Results of X-ray diffraction, electron paramagnetic resonance, surface structure and microwave absorption studies are reported in this paper and the experimental data correlated with the crystallite size and relatively cluster size variation in the applied field direction.

  20. Structural and Magnetic Properties of Codoped ZnO based Diluted Magnetic Semiconductors

    Microsoft Academic Search

    Bin-Bin Li; Hong-Lie Shen; Rong Zhang; Xiang-Qiang Xiu; Zhi Xie

    2007-01-01

    Zn1-xCoxO (x = 0.01, 0.02, 0.05, 0.10 and 0.20) diluted magnetic semiconductors are prepared by the sol-gel method. The structural and magnetic properties of the samples are studied using x-ray diffraction (XRD), extended x-ray absorption fine structure (EXAFS) and superconducting quantum interference device (SQUID). The XRD patterns does not show any signal of precipitates that are different from wurtzite type

  1. Laboratory Detection and Analysis of Organic Compounds in Rocks Using HPLC and XRD Methods

    NASA Technical Reports Server (NTRS)

    Dragoi, D.; Kanik, I.; Bar-Cohen, Y.; Sherrit, S.; Tsapin, A.; Kulleck, J.

    2004-01-01

    In this work we describe an analytical method for determining the presence of organic compounds in rocks, limestone, and other composite materials. Our preliminary laboratory experiments on different rocks/limestone show that the organic component in mineralogical matrices is a minor phase on order of hundreds of ppm and can be better detected using high precision liquid chromatography (HPLC). The matrix, which is the major phase, plays an important role in embedding and protecting the organic molecules from the harsh Martian environment. Some rocks bear significant amounts of amino acids therefore, it is possible to identify these phases using powder x-ray diffraction (XRD) by crystallizing the organic. The method of detection/analysis of organics, in particular amino acids, that have been associated with life will be shown in the next section.

  2. Studying Cellulose Fiber Structure by SEM, XRD, NMR and Acid Hydrolysis

    SciTech Connect

    Zhao, Haibo; Kwak, Ja Hun; Zhang, Z. Conrad; Brown, Heather M.; Arey, Bruce W.; Holladay, John E.

    2007-03-21

    Cotton linters were partially hydrolyzed in dilute acid and the morphology of remaining macrofibrils studied with Scanning Electron Microscopy (SEM) under various magnifications. The crystal region (microfibril bundles) in the macrofibrils was not altered by hydrolysis, and only amorphous cellulose was hydrolyzed and leached out from the macrofibrils. The diameter of microfibril bundles was 20-30 nm after the amorphous cellulose was removed by hydrolysis. XRD experiments confirm the unaltered diameter of the microfibrils after hydrolysis. The strong stability of these microfibril bundles in hydrolysis limits both the total sugar monomer yield and the size of nano particles or rods produced in hydrolysis. The large surface potential on the remaining microfibril bundles drives the agglomeration of macrofibrils.

  3. Nanocrystals magnetic contribution to FINEMET-type soft magnetic materials with Ge addition

    Microsoft Academic Search

    D. Muraca; J. Silveyra; M. Pagnola; V. Cremaschi

    2009-01-01

    Over the last years several works have been published in which magnetic and structural properties of soft magnetic nanocrystalline alloys were reported. Among these, there are a series of articles where the nanocrystals composition of FINEMET-type alloys with Ge addition was obtained by Mössbauer spectroscopy (MS) and X-ray diffraction (XRD). By considering a linear relationship between the magnetic moments of

  4. The proposed icy mineralogy package (XRD/XRF) for TandEM

    NASA Astrophysics Data System (ADS)

    Fortes, Andrew Dominic; Wood, Ian G.; Dobson, David P.; Fewster, Paul F.; Coustenis, Athena; Lebreton, Jean-Pierre

    Introduction: Understanding the geology of Titan's crust, and its interaction with the atmosphere, requires determination of the chemistry and mineralogy of surface materials which can only be achieved unambiguously using a combination of X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD). Here we describe an icy mineralogy package (IMP) consisting of a miniaturised XRD/XRF instrument designed primarily with Titan (and the TandEM ESA Cosmic Vision proposal [1]) in mind; however, the instrument is not predicated upon an a priori knowledge of surface mineralogy and consequently is applicable with little modification to any solar system body (rocky or icy). The proposed instrument is well suited to integration with other analytical tools, such as IR and UV Raman spectrometers. Instrument design: Two design concepts are currently under study, which differ in the complexity of the sample handling system, and the range of Bragg angles which may be observed. Both are focusing cameras, one (IMP senior) working in transmission, and the other (IMP junior) working in back-reflection. IMP jnr is intended for deployment on a static surface probe with no sample acquisition capability, collecting a single diffraction pattern through a window in the probe's underside. IMP snr is intended for deployment on a balloon with a sample collection arm able to deliver scoops of surface material to a rotating specimen stage. The latter may therefore be used to analyse many samples at geographically dispersed points. In each case we will use X-rays generated by high specific-activity radioisotope sources, 55 Fe and 241 Am. Our paper will present the results of the following activities: (a) compilation of a crystallographic database of materials expected on Titan's surface; (b) simulation of single-phase and polyphase diffraction data to illustrate the ease with which substances may be distinguished (even in complex mixtures); (c) blind tests of peak-matching software against synthetic diffraction data to estimate detection limits as a function of resolution and count times; and (d) trade-off studies of synthetic multilayer optics versus crystal monochromators. We will also report on environmental factors which affect (both positively and negatively) the likely instrument performance, including sample and atmosphere X-ray attenuation lengths. Summary: The proposed IMPs will be able to identify any crystalline substances (including organic polymers) present on Titan's surface at > 1 wt % levels, and quantify their relative abundance [2,3], as well as, in principle, estimate the abundance of any amorphous material. The focusing geometry maximises the flux and resolution obtainable from radioisotope sources and also has the advantage of illuminating a relatively large sample volume (compared to other mini-XRD designs); this improves the measured powder statistics. Most of the mass, and all of the power use is confined to the detector system (which is cooled passively by Titan's atmosphere) and data rates will be very small. The robustness of the technique renders it the method of choice for unambiguous determination of Titan's surface mineralogy. References: [1] Coustenis, A., et al. (2008) paper in press Astrophys. Instr. Methods. [2] Rietveld, H. (1969) J. Appl. Cryst. 2, 65-71. [3] Hill, R. J. & C. J. Howard (1987) J. Appl. Cryst. 20, 467-474.

  5. Data from the Mars Science Laboratory CheMin XRD/XRF instrument

    NASA Astrophysics Data System (ADS)

    Vaniman, David; Bristow, , David Blake, Tom; Des Marais, David; Achilles, Cherie; Spanovich, Ashwin Vasavada, , Robert Anderson, Joy Crisp, John Michael Morookian, Nicole; Yen, Albert; Bish, David; Chipera, Steve; Downs, Robert; Morrison, Shaunna; Farmer, Jack; Grotzinger, John; Stolper, Edward; Morris, , Douglas Ming, Richard; Rampe, Elizabeth; Treiman, Allan; Sarrazin, Philippe; MSL Science Team

    2013-04-01

    The CheMin instrument on the Mars Science Laboratory (MSL) rover Curiosity uses a Co tube source and a CCD detector to acquire mineralogy from diffracted primary X-rays and chemical information from fluoresced X-rays. CheMin has been operating at the MSL Gale Crater field site since August 5, 2012 and has provided the first X-ray diffraction (XRD) analyses in situ on a body beyond Earth. Data from the first sample collected, the Rocknest eolian soil, identify a basaltic mineral suite, predominantly plagioclase (~An50), forsteritic olivine (~Fo58), augite and pigeonite, consistent with expectation that detrital grains on Mars would reflect widespread basaltic sources. Minor phases (each <2 wt% of the crystalline component) include sanidine, magnetite, quartz, anhydrite, hematite and ilmenite. Significantly, about a third of the sample is amorphous or poorly ordered in XRD. This amorphous component is attested to by a broad rise in background centered at ~27° 2? (Co K?) and may include volcanic glass, impact glass, and poorly crystalline phases including iron oxyhydroxides; a rise at lower 2? may indicate allophane or hisingerite. Constraints from phase chemistry of the crystalline components, compared with a Rocknest bulk composition from the APXS instrument on Curiosity, indicate that in sum the amorphous or poorly crystalline components are relatively Si, Al, Mg-poor and enriched in Ti, Cr, Fe, K, P, S, and Cl. All of the identified crystalline phases are volatile-free; H2O, SO2 and CO2 volatile releases from a split of this sample analyzed by the SAM instrument on Curiosity are associated with the amorphous or poorly ordered materials. The Rocknest eolian soil may be a mixture of local detritus, mostly crystalline, with a regional or global set of dominantly amorphous or poorly ordered components. The Rocknest sample was targeted by MSL for "first time analysis" to demonstrate that a loose deposit could be scooped, sieved to <150 µm, and delivered to instruments in the body of the rover. A drilled sample of sediment in outcrop is anticipated. At the time of writing this abstract, promising outcrops are in range and this talk will provide an update on data collected with the CheMin instrument.

  6. Data from the Mars Science Laboratory CheMin XRD/XRF Instrument

    NASA Technical Reports Server (NTRS)

    Vaniman, David; Blake, David; Bristow, Tom; DesMarais, David; Achilles, Cherie; Anderson, Robert; Crips, Joy; Morookian, John Michael; Spanovich, Nicole; Vasavada, Ashwin; Yen, Albert; Bish, David; Chipera, Steve; Downs, Robert; Morrison, Shaunna; Farmer, Jack; Grotzinger, John; Stolper, Edward; Ming, Douglas; Morris, Richard; Rampe, Elizabeth; Treiman, Allan; Sarrazin, Philippe

    2013-01-01

    The CheMin instrument on the Mars Science Laboratory (MSL) rover Curiosity uses a Co tube source and a CCD detector to acquire mineralogy from diffracted primary X-rays and chemical information from fluoresced X-rays. CheMin has been operating at the MSL Gale Crater field site since August 5, 2012 and has provided the first X-ray diffraction (XRD) analyses in situ on a body beyond Earth. Data from the first sample collected, the Rocknest eolian soil, identify a basaltic mineral suite, predominantly plagioclase (approx.An50), forsteritic olivine (approx.Fo58), augite and pigeonite, consistent with expectation that detrital grains on Mars would reflect widespread basaltic sources. Minor phases (each <2 wt% of the crystalline component) include sanidine, magnetite, quartz, anhydrite, hematite and ilmenite. Significantly, about a third of the sample is amorphous or poorly ordered in XRD. This amorphous component is attested to by a broad rise in background centered at approx.27deg 2(theta) (Co K(alpha)) and may include volcanic glass, impact glass, and poorly crystalline phases including iron oxyhydroxides; a rise at lower 2(theta) may indicate allophane or hisingerite. Constraints from phase chemistry of the crystalline components, compared with a Rocknest bulk composition from the APXS instrument on Curiosity, indicate that in sum the amorphous or poorly crystalline components are relatively Si, Al, Mg-poor and enriched in Ti, Cr, Fe, K, P, S, and Cl. All of the identified crystalline phases are volatile-free; H2O, SO2 and CO2 volatile releases from a split of this sample analyzed by the SAM instrument on Curiosity are associated with the amorphous or poorly ordered materials. The Rocknest eolian soil may be a mixture of local detritus, mostly crystalline, with a regional or global set of dominantly amorphous or poorly ordered components. The Rocknest sample was targeted by MSL for "first time analysis" to demonstrate that a loose deposit could be scooped, sieved to <150 microns, and delivered to instruments in the body of the rover. A drilled sample of sediment in outcrop is anticipated. At the time of writing this abstract, promising outcrops are in range and this talk will provide an update on data collected with the CheMin instrument.

  7. XRD monitoring of ? self-irradiation in uranium-americium mixed oxides.

    PubMed

    Horlait, Denis; Lebreton, Florent; Roussel, Pascal; Delahaye, Thibaud

    2013-12-16

    The structural evolution under (241)Am self-irradiation of U(1-x)Am(x)O(2±?) transmutation fuels (with x ? 0.5) was studied by X-ray diffraction (XRD). Samples first underwent a preliminary heat treatment performed under a reducing atmosphere (Ar/H2(4%)) aiming to recover the previously accumulated structural defects. Over all measurements (carried out over up to a full year and for integrated doses up to 1.5 × 10(18) ?-decay events·g(-1)), only fluorite U(1-x)Am(x)O(2±?) solid solutions were observed. Within a few days after the end of the heat treatment, each of the five studied samples was slowly oxidized as a consequence of their move to air atmosphere, which is evidenced by XRD by an initial sharp decrease of the unit cell parameter. For the compounds with x ? 0.15, this oxidation occurred without any phase transitions, but for U0.6Am0.4O(2±?) and U0.5Am0.5O(2±?), this process is accompanied by a transition from a first fluorite solid solution to a second oxidized one, as the latter is thermodynamically stable in ambient conditions. In the meantime and after the oxidation process, (241)Am ? self-irradiation caused a structural swelling up to ?0.8 vol %, independently of the sample composition. The kinetic constants of swelling were also determined by regression of experimental data and are, as expected, dependent on x and thus on the dose rate. The normalization of these kinetic constants by sample ?-activity, however, leads to very close swelling rates among the samples. Finally, evolutions of microstrain and crystallite size were also monitored, but for the considered dose rates and cumulated doses, ? self-irradiation was found, within the limits of the diffractometer used, to have almost no impact on these characteristics. Microstrain was found to be influenced instead by the americium content in the materials (i.e., by the impurities associated with americium starting material and the increase of cationic charge heterogeneity with increasing americium content). PMID:24266774

  8. EPR, SEM and XRD investigation of ornamental limestone and marbles from some renowned Romanian quarries.

    NASA Astrophysics Data System (ADS)

    Covaci, D.; Costea, C.; Dumitras, D.; Duliu, O. G.

    2012-04-01

    Ornamental limestone and marble samples were collected and analysed by means of Electron Paramagnetic Resonance (EPR), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), in order to evidence any systematic peculiarities able to be used in further provenance studies as well as to get more detailed information regarding geochemistry and mineralogy of three of the most important deposits from Romania. In this respect, 20 samples of limestone (Arnota quarry, Capatani Mountains and Mateias South quarry, Iezer Mountains) and 9 of calci-dolomitic marble (Porumbacu de Sus quarry, Fagaras Mountains) were collected over a significant sampling area. EPR spectroscopy, primarily used to asset the degree of homogeneity of considered samples, evidenced, for both Arnota and Mateias South limestone, the presence of a typical six hyperfine lines spectrum of Mn2+ ions in calcite but no traces of Fe ferromagnetic clusters. A more careful investigation has showed that although within the same quarry, there were no significant differences regarding EPR spectra, the resonance lines were systematic narrower in the case of Mateias South samples which suggested a lower content of divalent manganese ions. The Porumbacu calci-dolomitic marble, presented a more intricate Mn2+ spectrum, consisting of a superposition of typical dolomitic and calcitic spectra. Again, the EPR spectra were almost identical, attesting, as in the previous cases, a relative uniform distribution of paramagnetic Mn2+ ions within quarry. In the case of SEM, scattered, back scattered and absorbed electron modes were used to visualise the mineral formations on the sample surfaces while an EDAX quantitative analysis was used to determine the content of the most abundant elements. Although, at a first inspection, both groups of limestone looked almost similar, displaying a great variety of randomly orientated micro-crystalline agglomeration, only in the case of Arnota samples, we have noticed the presence of some micron size graphite inclusions, potential proxies for further provenance studies. The Porumbacu South marble showed a different pattern, characterized by a more uniform crystallite distribution, all of them presenting almost perfect cleaving surfaces. EDAX results evidenced, excepting the dominant Ca and Mg (the last one in the case of Porumbacu de Sus marble), the presence, in small quantities, of some other element such as Fe, Ni, Cu and Zn whose content represent also a good provenance proxy. XRD investigation evidenced not only of the dominant calcite and dolomite mineral phases, but also other minor mineral fraction, whose presence could be well related to the content of mentioned trace elements. Principal Component and Cluster Analysis, finally used to classify all investigated samples, allowed us to group them in three cluster in accordance with their provenance.

  9. Structural Characterization of Ni-Substituted Hexaaluminate Catalysts Using EXAFS, XANES, XPS, XRD, and TPR

    SciTech Connect

    Gardner, J.; Spivey, J; Kugler, E; Campos, A; Hissam, J; Roy, A

    2010-01-01

    The structure of five Ni-substituted Ba{sub 0.75}Ni{sub y}Al{sub 12-y}O{sub 19-{delta}} hexaaluminate catalysts at various Ni loadings (y = 0.2, 0.4, 0.6, 0.8 and 1.0) was investigated using EXAFS, XANES, XPS, XRD, and TPR. As Ni-substitution into the hexaaluminate lattice is increased, the unit cell dimension decreases along the c axis. This systematic change is consistent with Ni substitution for Al{sup 3+} in the hexaaluminate crystalline structure. XANES analysis suggests that Ni-O bonding is stronger for Ni substituted into the hexaaluminate lattice, relative to that of bulk NiO. The average coordination numbers obtained from EXAFS indicate that Ni is preferentially exchanging with tetrahedrally coordinated Al{sup 3+} in the structure which predominates in regions of the hexaaluminate unit cell near the mirror plane. It is at these sites that, preferential substitution of Ni{sup 2+} likely occurs to minimize strain in the crystalline lattice.

  10. [Spectroscopic analysis of the crystallization mechanism of synthesized zeolite with XRD and FTIR approaches].

    PubMed

    Fan, Chun-hui; Ma, Hong-rui; Hua, Li

    2012-04-01

    Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used to indicate the crystallization characteristics and mechanism. The zeolite NaP1 was synthesized, and the CEC value reached to the maximum of 135 mmol/100g at 24 h. After the hydrothermal reaction for 12 h, the characteristic peak and metastable crystalline structure of zeolite NaP1 appeared, then the hydroxy sodalite products formed at 48 h. The crystallization process was the result of materials transformation: the elements of fly ash released into the liquid system for the melting effect of alkali solution, and the solid system played the role of skeleton in crystallization process, being the "source" and the "sink" of the reaction, respectively, and the achievements presented the crystallization mechanism of liquid-phase and solid-phase transformation. PMID:22715798

  11. Structures And Magnetization Of Defect-Associated Sites In Silicon

    SciTech Connect

    Chow, L.; Gonzalez-Pons, J. C.; Barco, E. del [Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Vanfleet, R. [Department of Physics, Brigham Young University, Provo, UT 84602 (United States); Misiuk, A. [Institute of Electron Technology (ITE), al. Lotnikow 32/46, Warsaw 02-668 Poland (Poland); Barcz, A. [Institute of Electron Technology (ITE), al. Lotnikow 32/46, Warsaw 02-668 Poland (Poland); Polish Academy of Science, Institute of Physics, al Lotnikow 32/46, Warsaw 02-668 Poland (Poland); Choi, E. S. [NHMFL, Florida State University, Tallahassee, FL 32310-3706 (United States); Chai, G. [Apollo Technologies, Inc. 205 Waymont Court, Suite 111, Lake Mary, FL 32746 (United States)

    2008-04-24

    To better understand the mechanism of the reported 'quasi-ferromagnetism' observed in Si ions self-implanted or irradiated silicon, we carry out high resolution transmission electron microscopy (HRTEM), magnetization measurements using superconducting quantum interference device (SQUID) magnetometer, and ferromagnetic resonance (FMR) measurements of the magnetic interaction of the defect-associated sites in silicon damaged by silicon self-implantation or energetic particle beams. The SQUID measurements showed that the silicon self-implanted sample has paramagnetic ordering. FMR measurements indicated the He{sup ++} irradiated sample has a ferromagnetic interaction and yields a Lande g-factor of 2.35.

  12. Structural, static and dynamic magnetic properties of dextran coated ?-Fe(2)O(3) nanoparticles studied by (57)Fe NMR, Mössbauer, TEM and magnetization measurements.

    PubMed

    Fardis, M; Douvalis, A P; Tsitrouli, D; Rabias, I; Stamopoulos, D; Kehagias, Th; Karakosta, E; Diamantopoulos, G; Bakas, T; Papavassiliou, G

    2012-04-18

    The structural and magnetic properties and spin dynamics of dextran coated and uncoated ?-Fe(2)O(3) (maghemite) nanoparticles have been investigated using high resolution transmission electron microscopy (HRTEM), (57)Fe nuclear magnetic resonance (NMR), Mössbauer spectroscopy and dc magnetization measurements. The HRTEM observations indicated a well-crystallized system of ellipsoid-shaped nanoparticles, with an average size of 10 nm. The combined Mössbauer and magnetic study suggested the existence of significant interparticle interactions not only in the uncoated but also in the dextran coated nanoparticle assemblies. The zero-field NMR spectra of the nanoparticles at low temperatures are very similar to those of the bulk material, indicating the same hyperfine field values at saturation in accord with the performed Mössbauer measurements. The T(2) NMR spin-spin relaxation time of the nanoparticles has also been measured as a function of temperature and found to be two orders of magnitude shorter than that of the bulk material. It is shown that the thermal fluctuations in the longitudinal magnetization of the nanoparticles in the low temperature limit may account for the shortening and the temperature dependence of the T(2) relaxation time. Thus, the low temperature NMR results are in accord with the mechanism of collective magnetic excitations, due to the precession of the magnetization around the easy direction of the magnetization at an energy minimum, a mechanism originally proposed to interpret Mössbauer experiments in magnetic nanoparticles. The effect of the surface spins on the NMR relaxation mechanisms is also discussed. PMID:22418594

  13. Elucidation of reaction mechanism involved in the formation of LaNiO3 from XRD and TG analysis

    NASA Astrophysics Data System (ADS)

    Dharmadhikari, Dipti V.; Athawale, Anjali A.

    2013-06-01

    The present work is focused on the synthesis and elucidation of reaction mechanism involved in the formation of LaNiO3 with the help of X-ray diffraction (XRD) and thermogravimetric (TG) analysis. LaNiO3 was synthesized by hydrothermal method by heating at 160°C under autogenous pressure for 6h. Pure phase product was obtained after calcining the hydrothermally activated product for 6h at 700°C. The various phases of the product obtained after hydrothermal treatment and calcination followed by the formation of pure phase nanocrystalline lanthanum nickel oxide could be determined from XRD analysis of the samples. The reaction mechanism and phase formation temperature has been interpreted by thermogravimetric analysis of the hydrothermally synthesized product and XRD analysis.

  14. Preparation of fluorescent magnetic nanodiamonds and cellular imaging.

    PubMed

    Chang, In Pin; Hwang, Kuo Chu; Chiang, Chi-Shiun

    2008-11-19

    Magnetic nanodiamonds were prepared via solid-state microwave arcing of a nanodiamond-ferrocene mixed powder in a focused microwave oven. High-resolution transmission electron microscope (HRTEM) images show that a magnetic nanodiamond is composed of iron nanoparticles encapsulated by graphene layers on the surface of nanodiamonds. Fluorescence property was introduced onto magnetic nanodiamonds by chemical modification of magnetic nanodiamonds via surface grafting of poly(acrylic acids) and fluorescein o-methacrylate. Fluorescent magnetic nanodiamonds are water soluble with a solubility of approximately 2.1 g/L. Cellular-imaging experiments show that fluorescent magnetic nanodiamonds could be ingested by HeLa cells readily in the absence of agonist (i.e., folate) moieties on the surface of nanodiamonds. PMID:18939829

  15. Transient Measurements Under Simulated Mantle Conditions - Simultaneous DTF-Ultrasonic Interferometry, X-Radiography, XRD

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Schilling, F. R.; Lathe, C.; Wunder, B.

    2004-12-01

    The interpretation of seismic data from the Earth's deep interior requires measurements of the physical properties of Earth materials under experimental simulated mantle conditions. Elastic wave velocity measurement by ultrasonic interferometry is an important tool for the determination of the elastic properties in multi-anvil devices. Whereas the classical sweep method is very time-consuming, the ultrasonic data transfer function technique (DTF), simultaneously generating all the frequencies used in the experiment, first described by Li et al. (2002), requires just few seconds to save the response of the system. The success of the technique substantially depends on the excitation function and the resolution used for saving the DTF (Mueller et al., 2004a). Background discussion as well as high pressure AƒA_A,A¿A,A 1/2 high temperature results demonstrate how to optimize the technique. All Ultrasonic interferometry allows highly precise travel time measurement at a sample enclosed in a high-pressure multi-anvil device. But under high pressure conditions the influence of sample deformation on the frequencies for destructive and constructive interference used for the evaluation of the elastic properties might be stronger than that from the shift of the elastic moduli. Consequently ultrasonic interferometry requires the exact sample length measurement under in situ conditions. X-ray imaging using brillant synchrotron radiation, called X-radiography, produces grey-scale images of the sample under in situ conditions by converting the X-ray image to an optical one by a CE-YAG-crystal. Saving the optical image by a CCD-camera after redirection by a mirrow, also requires few seconds. To derive the sample length, the different brightness of sample, buffer rod and reflector at the electronic image is evaluated (Mueller et al., 2004b). Contrary to XRD measurements, imaging the sample by X-rays requires a beam diameter larger than the sample length. Therefore the fixed primary slits of Max80 were exchanged by 4-blade high precision slits of Advanced Design Consulting, Inc. Some recent results on the non-quenchable high-P AƒA_A,A¿A,A 1/2 low-P clinoenstatite transition and to the quartz-coesite transition will be given to discuss the different interferometric techniques, including the XRD-data and X-radiography results, necessary to detect the phase transitions under in situ conditions and to measure the sample deformation. Li, B.; Chen, K.; Kung, J.; Liebermann, R.C.; Weidner, D.J., J. Phys.: Condens. Matter 14, 11337-11342, (2002). Mueller, H.J.; Lathe, C.; Wunder, B., In: J. Chen, Y. Wang, T. Duffy, G. Shen, L. Dobrzhinetskaya (eds.), Frontiers in High Pressure Research, Elsevier Science, submitted, (2004a). Mueller, H.J.; Schilling, F.R.; Lathe, C.; Lauterjung, J., In: J. Chen, Y. Wang, T. Duffy, G. Shen, L. Dobrzhinetskaya (eds.), Frontiers in High Pressure Research, Elsevier Science, in press, (2004b).

  16. Structural studies of GMR magnetic multilayers and spin-valves grown by DC sputtering

    Microsoft Academic Search

    Hong Geng

    2003-01-01

    The structures and growth characteristics of sputtered GMR magnetic multilayers and spin-valves have been characterized using conventional and high resolution transmission electron microscopy (CTEM and HRTEM). The first part of this dissertation focused on the characterization of polycrystalline Cu\\/Py (permalloy(TM)), Ag\\/Py, and Cu\\/CoZr spin-valves. For the Cu\\/Py spin-valves, structures with different Py thicknesses sputtered at different temperatures were examined. All

  17. Growth and Nanoscale Magnetic Properties of Ferromagnetic Nanowire Encapsulated Inside Carbon Nanotubes

    Microsoft Academic Search

    Yasuhiko Hayashi; T. Fujita; T. Tokunaga; B. Jang; M. Tanemura; G. A. J. Amaratunga

    2009-01-01

    We synthesize ferromagnetic Co nanowire, and Co\\/Pd multisegment nanowires encapsulated inside multi-walled carbon nanotubes CNTs (MWCNTs) by plasma-enhanced chemical vapor deposition (PECVD). High-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) were used to characterize the microstructures and elemental analyses of the nanowires. Quantitative magnetization measurements of Co nanowires encapsulated inside MWCNTs

  18. Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities.

    PubMed

    Bharathkumar, S; Sakar, M; K, Rohith Vinod; Balakumar, S

    2015-07-21

    This study demonstrates the fabrication of electrospun bismuth ferrite (BiFeO3/BFO) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively. The formation of these one dimensional (1D) nanostructures was mediated by the drum and plate collectors in the electrospinning process that yielded aligned and random nanofibers of BFO respectively. The single phase and rhombohedral crystal structure of the fabricated 1D BFO nanostructures are confirmed through X-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) studies indicated that the fabricated fibers are stoichiometric BFO with native oxidation states +3. The surface texture and morphology are analyzed using the field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) techniques. The average size of fibers in mat and mesh nanostructures is found to be 200 nm and 150 nm respectively. The band gap energy of BFO mat and mesh deduced from their UV diffuse reflectance spectra (UV-DRS) was found to be 2.44 eV and 2.39 eV, respectively, which evidenced the improved visible light receptivity of BFO mesh compared to that of the mat. Magnetization studies using a super conducting quantum interference device (SQUID) magnetometer revealed the weak ferromagnetic properties of BFO mesh and mat nanostructures that could emerge due to the dimension induced suppression of cycloidal spin structures. The photocatalytic degradation properties of the fibrous mesh are found to be enhanced compared to that of the mat. This could be attributed to the reduced band gap energy and an improved semiconductor band-bending phenomenon in the mesh that favoured the transportation of excited charge carriers to the photocatalyst-dye interfaces and the production of more number of reactive species that lead to the effective degradation of the dye molecules. PMID:26083677

  19. New magnetic nanoparticles for biotechnology.

    PubMed

    Hütten, Andreas; Sudfeld, Daniela; Ennen, Inga; Reiss, Günter; Hachmann, Wiebke; Heinzmann, Ulrich; Wojczykowski, Klaus; Jutzi, Peter; Saikaly, Wahib; Thomas, Gareth

    2004-08-26

    Paramagnetic carriers, which are linked to antibodies enable highly specific biological cell separations. With the colloidal synthesis of superparamagnetic Co and FeCo nanocrystals with superior magnetic moments the question about their potential to replace magnetite as the magnetically responsive component of magnetic beads is addressed. Starting from a magnetic analysis of the corresponding magnetophoretic mobility of Co and FeCo based alloys their synthesis and resulting microstructural and magnetic properties as function of the underlying particle size distribution are discussed in detail. The stability of the oleic acid ligand of Co nanocrystals has been investigated. The oxidation kinetics were quantified using magnetic measurements. As a result, this ligand system provides sufficient protection against oxidation. Furthermore, the kinetics of the synthesis of Fe(50)Co(50) nanoparticles has been monitored employing Fourier transform infra red (FT-IR) spectroscopy and is modeled using a consecutive decomposition and growth model. This model predicts the experimentally realized FeCo nanoparticle composition as a function of the particle size fairly well. High-resolution transmission electron microscopy (HRTEM) was performed to uncover the resulting microstructure and composition on a nanometer scale. PMID:15288940

  20. Structure and magnetic properties in CoCu granular alloys

    Microsoft Academic Search

    C. Meneghini; S. Mobilio; A. García-Prieto; M. L. F. Fdez-Gubieda

    2003-01-01

    Granular alloys, composed of magnetic clusters embedded in non-magnetic metallic matrices, can develop giant magnetoresistance effect after suitable preparation and thermal treatments. The structural effect of annealing on the structure of Co10Cu90 samples has been directly probed by in situ time resolved X-ray diffraction (TR-XRD) during thermal treatment. TR-XRD definitively proves the occurrence of an anomalous behaviour in the thermally

  1. Corrosion of Depleted Uranium in an Arid Environment: Soil-Geomorphology, SEM\\/EDS, XRD, and Electron Microprobe Analyses

    Microsoft Academic Search

    BRENDA J. BUCK; AMY L. BROCK; WILLIAM H. JOHNSON; APRIL L. ULERY

    2004-01-01

    Corrosion of anthropogenic uranium in natural environments is not well understood, but is important for determining potential health risks and mobility in the environment. A site in the southwestern United States contains depleted uranium that has been weathering for approximately 22 years. Soil-geomorphic, SEM\\/EDS, XRD, and electron microprobe analyses were conducted to determine the processes controlling the uranium corrosion. Schoepite

  2. Review of XRD-based quantitative analyses of clay minerals in soils: the suitability of mineral intensity factors

    Microsoft Academic Search

    Maren Kahle; Markus Kleber; Reinhold Jahn

    2002-01-01

    The determination of the types and relative amounts of the minerals present in soil forms an essential component of most soil characterization efforts. This paper reviews protocols for XRD-based quantitative clay mineral analysis in soils, with emphasis on methods using mineral intensity factors in combination with the so-called 100% approach. We summarize methodological differences and characteristic features and give information

  3. Experimental evidence for calcium-chloride ion pairs in the interlayer of montmorillonite. A XRD profile modeling approach

    E-print Network

    Boyer, Edmond

    Experimental evidence for calcium-chloride ion pairs in the interlayer of montmorillonite. A XRD layers which is best explained by the presence of cation ­ chloride ion pairs replacing the divalent be significantly altered as a consequence of storage-induced perturbations. For example, the use of concrete

  4. Effect of magnetic field on ball milled hard magnetic particles

    NASA Astrophysics Data System (ADS)

    Altuncevahir, B.; Poudyal, N.; Chakka, V. M.; Chen, K. H.; Black, T. D.; Liu, T. D.

    2004-03-01

    In this investigation, the powder particles of NdFeB and SmCo based alloys prepared by the ball milling in a uniform magnetic field are compared to those milled without an applied magnetic field. The ball milling was carried out for a total of 100 hours, and the powders were sampled every 25 hours. The particle size after 100 hours of milling was around 100 nm and the grain size in the particles was below 20 nm. The particles were then aligned in a magnetic field in hardening epoxy. It was found that the remanence ratios of the samples milled in an applied magnetic field were remarkably higher than those milled without field. XRD patterns also showed that the powder milled in magnetic field has better alignment than those milled without magnetic field. This technique is a novel approach to preparing anisotropic magnetic nanoparticles and has potential for producing high energy-product nanocomposite permanent magnets.

  5. Mineralogy and Magnetic Properties of Basaltic Substrate Soils: Kaho'olawe and Big Island, Hawaii

    Microsoft Academic Search

    Remke L. Van Dam; J. Bruce J. Harrison; Deidre A. Hirschfeld; Todd M. Meglich; Yaoguo Li; Ryan E. North

    2008-01-01

    Abbreviations: DTA, differential thermal analysis; Fed, dithionite-extractable Fe; Feo, oxalate-extractable Fe; TEM, time-domain electromagnetic; TGA, thermogravimetric analysis; UXO, unexploded ordnance; VRM, viscous remanent magnetization; XRD, x-ray diffraction spectroscopy; XRF, x-ray fl uorescence spectroscopy; ?, volume-specifi c magnetic susceptibility; ?, mass-specifi c magnetic susceptibility; ?fd%, frequency-dependent magnetic susceptibility; ?lf, low-frequency mass-specifi c magnetic susceptibility; ?T, temperature-dependent magnetic susceptibility. Magnetic behavior of

  6. Sol–gel route of synthesis of nanoparticles of MgFe 2O 4 and XRD, FTIR and VSM study

    Microsoft Academic Search

    A. Pradeep; P. Priyadharsini; G. Chandrasekaran

    2008-01-01

    Nanoparticles of MgFe2O4 are synthesized using sol–gel autocombustion method. Structural studies are carried out using X-ray diffraction (XRD). The XRD pattern of MgFe2O4 provides information about single-phase formation of spinel structure with cubic symmetry. The grain size and lattice constant are obtained using XRD data. The cation distribution is also proposed theoretically. The change in site preference of cations in

  7. The Chemical Composition of Serpentine\\/Chlorite in the Tuscaloosa Formation, United States Gulf Coast: EDX vs. XRD Determinations, Implications for Mineralogic Reactions and the Origin of Anatase

    Microsoft Academic Search

    P. C. RYANt; R. C. REYNOLDS

    1997-01-01

    The chemical composition of mixed-layer serpentine\\/chlorite (Sp\\/Ch) in Tuscaloosa Formation sandstone was analyzed by energy dispersive X-ray spectroscopy (EDX) in the scanning electron miscro- scope (SEM) and by X-ray diffraction (XRD). EDX results indicate little depth-controlled variation in composition, whereas XRD results suggest distinct decreases in octahedral Fe and tetrahedral A1. XRD- determined compositions appear to be erroneous and actually

  8. An exploratory method to detect tephras from quantitative XRD scans: Examples from Iceland and east Greenland marine sediments

    USGS Publications Warehouse

    Andrews, John T.; Eberl, D.D.; Kristjansdottir, G.B.

    2006-01-01

    Tephras, mainly from Iceland, are becoming increasingly important in interpreting leads and lags in the Holocene climate system across NW Europe. Here we demonstrate that Quantitative Phase Analysis of x-ray diffractograms of the 150 um fraction and identify these same peaks in XRD scans - two of these correlate geochemically and chronologically with Hekla 1104 and 3. At a distal site to the WNW of Iceland, on the East Greenland margin (core MD99-2317), the weight% of volcanic glass reaches values of 11% at about the time of the Saksunarvatn tephra. The XRD method identifies the presence of volcanic glass but not its elemental composition; hence it will assist in focusing attention on specific sections of sediment cores for subsequent geochemical fingerprinting of tephras. ?? 2006 SAGE Publications.

  9. Polycrystalline oxides formation during transient oxidation of (001) Cu-Ni binary alloys studied by in situ TEM and XRD.

    SciTech Connect

    Yang, J. C.; Li, Z. Q.; Sun, L.; Zhou, G. W.; Eastman, J. A.; Fong, D. D.; Fuoss, P. H.; Baldo, P. M.; Rehn, L. E.; Thompson, L. J.; Materials Science Division; Univ.of Pittsburgh; State Univ. of New York at Binghamton

    2009-01-01

    The nucleation and growth of Cu{sub 2}O and NiO islands due to oxidation of Cu{sub x}Ni{sub 1-x} (001) films were monitored, at various temperatures, by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) and in situ synchrotron X-ray diffraction (XRD). In remarkable contrast to our previous observations of Cu and Cu-Au oxidation, irregular-shaped polycrystalline oxide islands formed with respect to the Cu-Ni alloy film, and an unusual second oxide nucleation stage was noted. In situ XRD experiments revealed that NiO formed first epitaxially, then other orientations appeared, and finally polycrystalline Cu{sub 2}O developed as the oxidation pressure was increased. The segregation of Ni and Cu towards or away, respectively, from the alloy surface during oxidation could disrupt the surface and cause polycrystalline oxide formation.

  10. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system

    Microsoft Academic Search

    B. J. Reardon; C. R. Hubbard

    1992-01-01

    X-ray powder patterns for the phases in the CaO-SrO-PbO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a calculated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here

  11. A general method for the recovery of pure powder XRD patterns from complex mixtures using no a priori information

    Microsoft Academic Search

    Liangfeng Guo; Fethi Kooli; Marc Garland

    2004-01-01

    The recovery of pure component spectra from multi-component mixtures is one of the most common analytical problems in the chemical sciences. In cases where separation of the unknown components is not possible, the problem is often intractable. In materials science research, X-ray diffraction (XRD) and particularly X-ray powder diffraction (XRPD) are perhaps the primary characterization tools. Recently, we introduced band-target

  12. Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy

    Microsoft Academic Search

    Jacqueline R Houston; Robert S Maxwell; Susan A Carroll

    2009-01-01

    Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline

  13. A multi-technique approach by XRD, XRF, FT-IR to characterize the diagenesis of dinosaur bones from Spain

    Microsoft Academic Search

    Giampaolo Piga; Andrés Santos-Cubedo; Antonio Brunetti; Massimo Piccinini; Assumpciò Malgosa; Emilio Napolitano; Stefano Enzo

    2011-01-01

    A combined investigation by X-ray fluorescence (XRF), Fourier Transform Infrared spectroscopy (FT-IR), Raman spectroscopy and powder X-ray Diffraction (XRD), supplemented with the Rietveld analysis, was conducted on sixty Spanish dinosaur bone specimens from Upper Jurassic\\/Lower Cretaceous to Upper Cretaceous age to investigate taphonomy and diagenetic processes. The diffraction approach assessed in all specimens the presence of fluorapatite at various levels

  14. Crystal Structure and Morphology Dependence of the Phase of Mollusc Shell: A Case Study of XRD, SEM and ESR

    NASA Astrophysics Data System (ADS)

    Siriprom, W.; Kaewkhao, J.; Phachana, K.; Limsuwan, P.

    2011-01-01

    The aim of this study is to investigate the physical properties in the Paphia undulate and Amusium pleuronectes shells collected from the coastal area of Chonburi province, Thailand. The crystal structure of the shells was studied by x-ray diffraction (XRD). The XRD patterns spectra reveal that the Paphia undulate shells and Amusium pleuronectes shells are made of a pure aragonite phase, and a mixture phase of aragonite and calcite, respectively, the identification and quantitative analysis were performed by using the Rietveld method. In this study, we also used the scanning electron microscope (SEM) to study the Morphology of the Paphia undulate shells and Amusium pleuronectes shells. The results on SEM micrographs agree well with those of XRD. In addition, the ions in the shell samples were also studied by Electron Spin Resonance Spectroscopy (ESR). The ESR spectra show that the samples of both shells were consisting of Mn2+ ions. The pattern of the ESR spectrum is thus strongly influenced by the environment of the paramagnetic ions, and then it can be used to identification of crystal structure of mollusc shell

  15. Transmission X-ray Diffraction (XRD) Patterns Relevant to the MSL Chemin Amorphous Component: Sulfates And Silicates

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Rampe, E. B.; Graff, T. G.; Archer, P. D., Jr.; Le, L.; Ming, D. W.; Sutter, B.

    2015-01-01

    The Mars Science Laboratory (MSL) CheMin instrument on the Curiosity rover is a transmission X-ray diffractometer (Co-Kalpha radiation source and a approx.5deg to approx.52deg 2theta range) where the analyzed powder samples are constrained to have discrete particle diameters <150 microns by a sieve. To date, diffraction patterns have been obtained for one basaltic soil (Rocknest (RN)) and four drill fines of coherent rock (John Klein (JK), Cumberland (CB), Windjana (WJ), and Confidence Hills (CH)). The CheMin instrument has detected and quantified the abundance of both primary igneous (e.g., feldspar, olivine, and pyroxene) and secondary (e.g., Ca-sulfates, hematite, akaganeite, and Fe-saponite) minerals. The diffraction patterns of all CheMin samples are also characterized by a broad diffraction band centered near 30deg 2theta and by increasing diffraction intensity (scattering continuum) from approx.15deg to approx.5deg, the 2theta minimum. Both the broad band and the scattering continuum are attributed to the presence of an XRD amorphous component. Estimates of amorphous component abundance, based on the XRD data itself and on mass-balance calculations using APXS data crystalline component chemistry derived from XRD data, martian meteorites, and/or stoichiometry [e.g., 6-9], range from approx.20 wt.% to approx.50 wt.% of bulk sample. The APXSbased calculations show that the amorphous component is rich in volatile elements (esp. SO3) and is not simply primary basaltic glass, which was used as a surrogate to model the broad band in the RN CheMin pattern. For RN, the entire volatile inventory (except minor anhydrite) is assigned to the amorphous component because no volatile-bearing crystalline phases were reported within detection limits [2]. For JK and CB, Fesaponite, basanite, and akaganeite are volatile-bearing crystalline components. Here we report transmission XRD patterns for sulfate and silicate phases relevant to interpretation of MSL-CheMin XRD amorphous components.

  16. Characterizing the Phyllosilicates and Amorphous Phases Found by MSL Using Laboratory XRD and EGA Measurements of Natural and Synthetic Materials

    NASA Technical Reports Server (NTRS)

    Rampe, Elizabeth B.; Morris, Richard V.; Chipera, Steve; Bish, David L.; Bristow, Thomas; Archer, Paul Douglas; Blake, David; Achilles, Cherie; Ming, Douglas W.; Vaniman, David; Crisp, Joy A.; DesMarais, David J.; Downs, Robert; Farmer, Jack D.; Morookian, John Michael; Morrison, Shaunna; Sarrazin, Philippe; Spanovich, Nicole; Treiman, Allan H.; Yen, Albert S.

    2013-01-01

    The Curiosity Rover landed on the Peace Vallis alluvial fan in Gale crater on August 5, 2012. A primary mission science objective is to search for past habitable environments, and, in particular, to assess the role of past water. Identifying the minerals and mineraloids that result from aqueous alteration at Gale crater is essential for understanding past aqueous processes at the MSL landing site and hence for interpreting the site's potential habitability. X-ray diffraction (XRD) data from the CheMin instrument and evolved gas analyses (EGA) from the SAM instrument have helped the MSL science team identify phases that resulted from aqueous processes: phyllosilicates and amorphous phases were measure in two drill samples (John Klein and Cumberland) obtained from the Sheepbed Member, Yellowknife Bay Fm., which is believed to represent a fluvial-lacustrine environment. A third set of analyses was obtained from scoop samples from the Rocknest sand shadow. Chemical data from the APXS instrument have helped constrain the chemical compositions of these secondary phases and suggest that the phyllosilicate component is Mg-enriched and the amorphous component is Fe-enriched, relatively Si-poor, and S- and H-bearing. To refine the phyllosilicate and amorphous components in the samples measured by MSL, we measured XRD and EGA data for a variety of relevant natural terrestrial phyllosilicates and synthetic mineraloids in laboratory testbeds of the CheMin and SAM instruments. Specifically, Mg-saturated smectites and vermiculites were measured with XRD at low relative humidity to understand the behavior of the 001 reflections under Mars-like conditions. Our laboratory XRD measurements suggest that interlayer cation composition affects the hydration state of swelling clays at low RH and, thus, the 001 peak positions. XRD patterns of synthetic amorphous materials, including allophane, ferrihydrite, and hisingerite were used in full-pattern fitting (FULLPAT) models to help determine the types and abundances of amorphous phases in the martian rocks and sand shadow. These models suggest that the rocks and sand shadow are composed of approx 30% amorphous phases. Sulfate-adsorbed allophane and ferrihydrite were measured by EGA to further understand the speciation of the sulfur present in the amorphous component. These data indicate that sulfate adsorbed onto the surfaces of amorphous phases could explain a portion of the SO2 evolution in the Rocknest SAM data. The additional constraints placed on the mineralogy and chemistry of the aqueous alteration phases through our laboratory measurements can help us better understand the nature of the fluids that affected the different samples and devise a history of aqueous alteration for the Sheepbed Member of the Yellowknife Bay Fm. at Gale crater.

  17. Comparative investigation of Fourier Transform Infrared (FT-IR) spectroscopy and X-ray Diffraction (XRD) in the determination of cotton fiber crystallinity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite considerable efforts in developing the curve-fitting protocol to evaluate the crystallinity index (CI) from the X-ray diffraction (XRD) measurement, in its present state XRD procedure can only provide a qualitative or semi-quantitative assessment of the amounts of crystalline or amorphous po...

  18. Sol–gel synthesis, structure and magnetic properties of Mn-doped ZnO diluted magnetic semiconductors

    Microsoft Academic Search

    Yingjing Jiang; Wei Wang; Chengbin Jing; Chunyue Cao; Junhao Chu

    2011-01-01

    2.5, 5, 10 and 15% Mn-doped ZnO diluted magnetic semiconductors (DMSs) were prepared via an ethyl acetoacetate-aided sol–gel process. The 5% Mn-doped ZnO consists of 20–50nm spheroid-like particles and has a wurtzite phase. Existence of nanoscale ZnMnO3 clusters in this sample is confirmed by HRTEM analysis. Vegard's law calculation reveals that about 2.6% Mn atoms have been incorporated into ZnO

  19. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system

    NASA Astrophysics Data System (ADS)

    Reardon, B. J.; Hubbard, C. R.

    1992-02-01

    X-ray powder patterns for the phases in the CaO-SrO-PbO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a calculated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca,Sr)2PbO4 solid solution series and are recommended for the PDF.

  20. Astrobiological Significance of Definitive Mineralogical Analysis of Martian Surface Samples Using the CheMin XRD/XRF Instrument

    NASA Technical Reports Server (NTRS)

    Feldman, S. M.; Blake, D. F.; Sarrazin, P.; Bish, D. L.; Chipera, S. J.; Vaniman, D. T.; Collins, S.

    2004-01-01

    The search for evidence of habitability, or of extant or extinct life on Mars, will initially be a search for evidence of past or present conditions supportive of life. The three key requirements for the emergence of life are thought to be liquid water; a suitable energy source; and chemical building blocks. CheMin is a miniaturized XRD/XRF (X-Ray diffraction / X-ray fluorescence) instrument which has been developed for definitive mineralogic analysis of soils and rocks on the Martian surface. The CheMin instrument can provide information that is highly relevant to each of these habitability requirements as summarized below.

  1. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system

    SciTech Connect

    Reardon, B.J.; Hubbard, C.R.

    1992-02-01

    X-ray powder patterns for the phases in the CaO-SrO-PbO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a calculated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca,Sr){sub 2}PbO{sub 4} solid solution series and are recommended for the PDF.

  2. Synthesis of metal complexes involving Schiff base ligand with methylenedioxy moiety: Spectral, thermal, XRD and antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Sundararajan, M. L.; Jeyakumar, T.; Anandakumaran, J.; Karpanai Selvan, B.

    2014-10-01

    Metal complexes of Zn(II), Cd(II), Ni(II), Cu(II), Fe(III), Co(II), Mn(II) Hg(II), and Ag(I) have been synthesized from Schiff base ligand, prepared by the condensation of 3,4-(methylenedioxy)aniline and 5-bromo salicylaldehyde. All the compounds have been characterized by using elemental analysis, molar conductance, FT-IR, UV-Vis, 1H NMR, 13C NMR, mass spectra, powder XRD and thermal analysis (TG/DTA) technique. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The FT-IR, 1H NMR, 13C NMR and UV-Vis spectral data suggest that the ligand coordinate to the metal atom by imino nitrogen and phenolic oxygen as bidentate manner. Mass spectral data further support the molecular mass of the compounds and their structure. Powder XRD indicates the crystalline state and morphology of the ligand and its metal complexes. The thermal behaviors of the complexes prove the presence of lattice as well as coordinated water molecules in the complexes. Melting point supports the thermal stability of all the compounds. The in vitro antimicrobial effects of the synthesized compounds were tested against five bacterial and three fungal species by well diffusion method. Antioxidant activities have also been performed for all the compounds. Metal complexes show more biological activity than the Schiff base.

  3. Some critical aspects of FT-IR, TGA, powder XRD, EDAX and SEM studies of calcium oxalate urinary calculi.

    PubMed

    Joshi, Vimal S; Vasant, Sonal R; Bhatt, J G; Joshi, Mihir J

    2014-06-01

    Urinary calculi constitute one of the oldest afflictions of humans as well as animals, which are occurring globally. The calculi vary in shape, size and composition, which influence their clinical course. They are usually of the mixed-type with varying percentages of the ingredients. In medical management of urinary calculi, either the nature of calculi is to be known or the exact composition of calculi is required. In the present study, two selected calculi were recovered after surgery from two different patients for detailed examination and investigated by using Fourier-Transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy and energy dispersive analysis of X-rays (EDAX) techniques. The study demonstrated that the nature of urinary calculi and presence of major phase in mixed calculi could be identified by FT-IR, TGA and powder XRD, however, the exact content of various elements could be found by EDAX only. PMID:25204087

  4. Characterization of stabilized/solidified refinery oily sludge and incinerated refinery sludge with cement using XRD, SEM and EXAFS.

    PubMed

    Karamalidis, Athanasios K; Psycharis, Vasileios; Nicolis, Ioannis; Pavlidou, Eleni; Benazeth, Simone; Voudrias, Evangelos A

    2008-08-01

    Solidification/stabilization (S/S) of refinery oily sludge and incinerated oily sludge (ash) with cement type I42.5 and II42.5 was investigated using, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS) and Extended X-ray Absorption Fine Structure (EXAFS). The results showed that delayed ettringite formation (DEF) and major cement hydration reactions occurred. XRD analysis of S/S oily sludge samples revealed cement-bearing solid phases, such as portlandite, calcite, C(3)S, C(2)S and C(4)AF. SEM analysis, confirmed ettringite at solidified oily sludge samples. Solidified ash samples contained ettringite substituted by chromates. However, solid phases found in solidified ash samples with I42.5 cement showed minor variation in type and structure compared to those observed in solidified ash samples with II42.5 cement. Fe K edge EXAFS analysis revealed the presence of iron oxides in both S/S wastes. The comparison between spectra of the S/S resulting materials and the ones of their original components, showed that the first sphere Fe-O distances were longer than in the pure iron oxide thereby providing evidence that the resulting materials were not simple mixtures, but products of a reaction that modified the local environment of iron. PMID:18584430

  5. Magnetic measurements on ??CS{sub 2}U{sub 4}O{sub 12}

    SciTech Connect

    Kanrar, Buddhadev, E-mail: nlmisra@barc.gov.in; Misra, N. L., E-mail: nlmisra@barc.gov.in [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Sastry, P. U. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Dube, V.; Ravikumar, G. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    Magnetic and XRD measurements on ??CS{sub 2}U{sub 4}O{sub 12} having uranium in mixed valent states of U (V) and U (VI) have been made. The study reveals that the compound undergoes an antiferromagnetic transition below 25K and an anomalous magnetic behavior was seen around 75K. This anomalous behavior indicates towards a structural phase transition. However, the low temperature XRD could not confirm this observation.

  6. Characterization of minerals in air dust particles in the state of Tamilnadu, India through FTIR, XRD and SEM analyses

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, R.; Rajkumar, P.

    2014-11-01

    The abstract of this paper explains the presence of minerals in air which causes great concern regarding public health issues. The spectroscopic investigation of air dust particles of several samples in various locations in the state of Tamilnadu, India is reported. Qualitative analyses were carried out to determine the major and minor constituent minerals present in the samples based on the FTIR, XRD absorption peaks. This study also identified the minerals like quartz, asbestos, kaolinite, calcite, hematite, montmorillonite, nacrite and several other trace minerals in the air dust particles. The presents of quartz is mainly found in all the samples invariably. Hence the percentage of quartz and its crystalline nature were determined with the help of extinction co-efficient and crystallinity index respectively. The shape and size of the particulates are studied with SEM analysis.

  7. Preparation of biocompatible magnetite-carboxymethyl cellulose nanocomposite: Characterization of nanocomposite by FTIR, XRD, FESEM and TEM

    NASA Astrophysics Data System (ADS)

    Habibi, Neda

    2014-10-01

    The preparation and characterization of magnetite-carboxymethyl cellulose nano-composite (M-CMC) material is described. Magnetite nano-particles were synthesized by a modified co-precipitation method using ferrous chloride tetrahydrate and ferric chloride hexahydrate in ammonium hydroxide solution. The M-CMC nano-composite particles were synthesized by embedding the magnetite nanoparticles inside carboxymethyl cellulose (CMC) using a freshly prepared mixture of Fe3O4 with CMC precursor. Morphology, particle size, and structural properties of magnetite-carboxymethyl cellulose nano-composite was accomplished using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. As a result, magnetite nano-particles with an average size of 35 nm were obtained. The biocompatible Fe3O4-carboxymethyl cellulose nano-composite particles obtained from the natural CMC polymers have a potential range of application in biomedical field.

  8. Structural Properties of AlN Films with Oxygen Content Deposited by Reactive Magnetron Sputtering:. XRD and XPS Characterization

    NASA Astrophysics Data System (ADS)

    García-Méndez, Manuel; Morales-Rodríguez, Santos; Shaji, Sadasivan; Krishnan, Bindu; Bartolo-Pérez, Pascual

    A set of aluminium nitride (AlN) and oxidized AlN (AlNO) thin films were grown with the technique of direct current (dc) reactive magnetron sputtering. The main purpose of this investigation is to explore the influence of the oxygen on the structural properties of AlN and AlNO films. The crystalline properties and chemical identification of phases were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Electrical properties were analyzed from I-V measurements. It was found that films crystallized under the AlN würzite structure and presented a polycrystalline preferential growth along [0001] direction, perpendicular to substrate. Small amounts of secondary aluminium oxide phases were detected too. The oxide phases can induce defects, which can alter crystallinity of films.

  9. Reciprocal space XRD mapping with varied incident angle as a probe of structure variation within surface depth

    SciTech Connect

    Yang, Qiguang [Norfolk State University; Williams, Frances [Norfolk State University; Zhao, Xin [JLAB; Reece, Charles E. [JLAB; Krishnan, Mahadevan [AASC, San Leandro, California

    2013-09-01

    In this study, we used a differential-depth X-Ray diffraction Reciprocal Spacing Mapping (XRD RSM) technique to investigate the crystal quality of a variety of SRF-relevant Nb film and bulk materials. By choosing different X-ray probing depths, the RSM study successfully revealed evolution the of materials? microstructure after different materials processes, such as energetic condensation or surface polishing. The RSM data clearly measured the materials? crystal quality at different thickness. Through a novel differential-depth RSM technique, this study found: I. for a heteroepitaxy Nb film Nb(100)/MgO(100), the film thickening process, via a cathodic arc-discharge Nb ion deposition, created a near-perfect single crystal Nb on the surface?s top-layer; II. for a mechanically polished single-crystal bulk Nb material, the microstructure on the top surface layer is more disordered than that in-grain.

  10. Degradation of dental ZrO2-based materials after hydrothermal fatigue. Part I: XRD, XRF, and FESEM analyses.

    PubMed

    Perdigão, Jorge; Pinto, Ana M; Monteiro, Regina C C; Braz Fernandes, Francisco M; Laranjeira, Pedro; Veiga, João P

    2012-01-01

    The aim was to investigate the effect of simulated low-temperature degradation (s-LTD) and hydrothermal fatigue on the degradation of three ZrO(2)-based dental materials. Lava, IPS, and NanoZr discs were randomly assigned to (1) Control-Storage in distilled water at 37°C; (2) Aging at 134°C for 5 h (s-LTD); (3) Thermocycling in saliva for 30,000 cycles (TF). XRD revealed that ZrO(2) m phase was identified in all groups but TF increased the m phase only for Lava. Under the FESEM, Lava showed no alterations under s-LTD, but displayed corrosion areas up to 60 µm wide after TF. We conclude that TF accelerated the degradation of Lava through an increase in the m phase and grain pull-out from the material surface. PMID:22447060

  11. Anisotropically structured magnetic aerogel monoliths

    NASA Astrophysics Data System (ADS)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and titania nanoparticles. See DOI: 10.1039/c4nr04694c

  12. Preparation and characterization of amino-functionalized magnetic nanogels via photopolymerization for MRI applications.

    PubMed

    Gong, Yanbao; Fan, Mingxia; Gao, Feng; Hong, Jun; Liu, Shunying; Luo, Shufang; Yu, Jiahui; Huang, Jin

    2009-07-01

    To design peptide-targeted iron oxide as magnetic resonance imaging (MRI) contrast agents, amino-functionalized magnetic nanogels were prepared by using N-(2-aminoethyl) methacrylamide hydrochloride (AEM x HCl) as monomer via new photochemical approach. Their chemical structure and composition were characterized by Fourier transform infrared spectra (FTIR) and thermogravimetric analyses (TGA). The core-shell structure of magnetic nanogels was confirmed by high-resolution transmission electron microscopy (HRTEM). The good storage stability, high magnetic content (88.7%), high saturation magnetizations and superparamagnetic behavior suggested their great potentials as MRI contrast agents, which were confirmed by their measurements of r(2) and coronal image of the crossing of mouse kidney. PMID:19278838

  13. Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

    SciTech Connect

    Garza-Navarro, Marco [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Torres-Castro, Alejandro, E-mail: alejandro.torrescs@uanl.edu.m [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon 66600 (Mexico); Gonzalez, Virgilio; Ortiz, Ubaldo [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon 66600 (Mexico); De la Rosa, Elder [Centro de Investigaciones en Optica, A.P. 1-948, Leon Gto. 37160 (Mexico)

    2010-01-15

    In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. - Graphical abstract: Biopolymer chitosan was used as stabilization media to synthesize both magnetite and magnetite/silver core/shell nanoparticles. Results of HRTEM and NBD patterns confirm core/shell morphology of the obtained nanoparticles. It was found that the composites show diluted magnet-like behavior.

  14. Mineralogical Capabilities of the CheMin XRD/XRF instrument on Mars Science Laboratory (MSL ’11)

    NASA Astrophysics Data System (ADS)

    Blake, D. F.; Vaniman, D. T.; Yen, A. S.; Chen, C.; Sarrazin, P.; Bish, D. L.; Chipera, S.; Morris, R. V.

    2009-12-01

    A principal goal of the Mars Science Laboratory (MSL ‘11) mission is to identify and characterize present or past habitable environments on Mars. By determining the mineralogical composition of rocks or soil, one can often deduce the conditions under which they formed, or their subsequent diagenetic or metamorphic history. The CheMin mineralogical instrument [1-3] will return quantitative X-ray diffraction data (XRD) and qualitative X-ray fluorescence data (XRF; 14 < Z < 92) from scooped soils and drilled rock powders collected from the Mars surface. Small amounts (45-65 mm3) of sample material sieved to <150 µm will be delivered through a funnel to one of 27 reuseable sample cells located on a sample wheel. Sample cells are 8-mm diameter discs bounded by 7-µm thick Mylar or Kapton windows spaced 170 µm apart. Within this volume, the sample is shaken by piezoelectric vibration at sonic frequencies, causing the powder to flow past a narrow, collimated X-ray beam in random orientations during the course of an analysis. CheMin is designed to have a Minimum Detection Limit (MDL) of <3% by mass, accuracy better than 15% and precision better than 10% for phases present in concentrations >4X MDL (12%). CheMin uses a Co X-ray tube so that absorption in iron-rich samples is minimized. The resolution of the diffraction patterns is <0.35° 2?, and the angular measurement range is 4-55° 2?. The capabilities of the FM instrument were tested during ThermoVac using mineral and ceramic standards contained on the FM sample wheel. Standards include 88:12 and 97:3 mixtures of beryl:quartz for assessment of the accuracy and precision of quantitative analyses, miminum detection limits, 2? range and 2? resolution; a compositionally diverse ceramic material for XRF evaluation; arcanite (K2SO4); and an amphibole. Analyses were performed under Mars atmospheric pressure at a range of Rover Avionics Mounting Platform (RAMP) temperatures from -40C to +26C. Within the predicted Mars RAMP operating temperatures of 0C to +20C, peak-to-background ratios in the XRD pattern and FWHM of elemental peaks in XRF spectra were within proscribed limits. The beryl:quartz mixtures show some anomalous phase segregation during sample shaking that is being investigated. Mineral detection and energy resolution capabilites meet or exceed requirements. References: [1] http://msl-scicorner.jpl.nasa.gov/Instruments/CheMin/. [2] LPSC40 #1484 (2009). [3] Martian Phyllosilicates: Recorders of Aqueous Processes #7006 (2008).

  15. The thermal, magnetic, and structural characterization of the crystallization kinetics of amorphous soft magnetic materials

    Microsoft Academic Search

    A. C. Hsiao

    2002-01-01

    Summary form only given. The characterization of the crystallization kinetics of amorphous soft magnetic materials, namely NANOPERM™, an Fe88Zr7B4Cu1 amorphous soft magnetic alloy, and its derivatives, is presented. Crystallization kinetics are observed isothermally and non-isothermally by differential scanning calorimetry (DSC), synchrotron x-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Vibrating sample magnetometry and x-ray diffractometry, used concurrently with differential scanning

  16. Chemical diffusion: Another factor affecting the magnetoresistance ratio in Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junction

    SciTech Connect

    Yang, Y.; Wang, W. X.; Yao, Y.; Liu, H. F.; Han, X. F.; Yu, R. C. [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Naganuma, H.; Sakul, T. S. [Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2012-07-02

    This letter investigates the microstructure and mean inner potential (MIP) profile of Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junctions (MTJs) by high resolution transmission electron microscopy (HRTEM) and electron holography, respectively. The inconspicuous crystallization of MgO barrier is confirmed by HRTEM in the post-annealed sample at 250 Degree-Sign C. An obvious MIP difference is displayed in the Ta layers between the top and bottom of the MTJ, and elemental content difference of them is confirmed by energy dispersive spectroscopy. These results imply that the chemical diffusion can also give rise to a lower tunnel magnetoresistance ratio besides the inconspicuous crystallization of MgO barrier.

  17. ArF excimer laser epitaxy of Si xGe 1- x alloys studied by XRD and XPS

    NASA Astrophysics Data System (ADS)

    Larciprete, R.; Willmott, P.; Martelli, S.; Cesile, M. C.; Borsella, E.; Chiussi, S.; González, P.; León, B.

    1996-10-01

    The formation of SiGe alloys was obtained by ArF excimer laser induced epitaxy of thin a-Ge films deposited by Laser-CVD on Si(100) substrates. The alloying process was studied as a function of the thickness of the Ge overlayer, which ranged between 10 and 70 nm. In order to investigate the early stage of the Ge and Si intermixing, single pulse irradiation was performed at fluence (0.49 J/cm 2) appropriate to melt the Ge overlayer and a certain thickness of the underlying substrate. XRD and XPS depth profile analysis revealed the formation of graded alloys, showing high Ge content in the near-surface layer and Si rich alloy regions in the proximity of the alloy/substrate interface. Although Ge was redistributed over lengths predictable by heat flow numerical model calculation, other mechanisms (such as Ge segregation and/or strain field effects) besides diffusion, seem to regulate the observed alloy concentration profiles. The altered surface morphology exhibited after laser processing by the sample having the thickest Ge overlayer sets an upper limit for the thickness of the a-Ge film, which in the present irradiation conditions is about 40 nm.

  18. In Situ XAS and XRD Studies of Substituted Spinel Lithium Manganese Oxides in the 4-5 V Region

    SciTech Connect

    McBreen, J.; Mukerjee, S.; Yang, X. Q.; Sun, X.; Ein-Eli, Y.

    1998-11-01

    Partial substitution of Mn in lithium manganese oxide spinel materials by Cu and Ni greatly affects the electrochemistry and the phase behavior of the cathode. Substitution with either metal or with a combination of both shortens the 4.2 V plateau and results in higher voltage plateaus. In situ x-ray absorption (XAS) studies indicate that the higher voltage plateaus are related to redox processes on the substituents. In situ x-ray diffraction (XRD) on LiCu{sub 0.5}Mn{sub 1.5}O{sub 4} shows single phase behavior during the charge and discharge process. Three phases are observed for LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} and two phases are observed in the case of LiNi{sub 0.25}Cu{sub 0.25}Mn{sub 1.5}O{sub 4}. The electrolyte stability is dependent on both the operating voltage and the cathode composition. Even though Ni substituted materials have lower voltages, the electrolyte is more stable in cells with the Cu substituted materials.

  19. Shades of green in 15th century paintings: combined microanalysis of the materials using synchrotron radiation XRD, FTIR and XRF

    NASA Astrophysics Data System (ADS)

    Salvadó, Nati; Butí, Salvador; Cotte, Marine; Cinque, Gianfelice; Pradell, Trinitat

    2013-04-01

    A representative selection of green paintings from fifteenth century Catalonia and the Crown of Aragon are analyzed by a combination of synchrotron radiation microanalytical techniques including FTIR, XRD, and XRF. The green pigments themselves are found to be a mixture of copper acetates/basic copper acetates and basic copper chlorides. Nevertheless, a broader range of green shades were obtained by mixing the green pigment with yellow, white, and blue pigments and applied forming a sequence of micrometric layers. Besides the nature of the pigments themselves, degradation and reaction products, such as carboxylates, formates and oxalates were also identified. Some of the copper based compounds, such as the basic copper chloride, may be either part of the original pigment or a weathering product. The high resolution, high brilliance, and small footprint of synchrotron radiation proved to be essential for the analysis of those submillimetric paint layers made of a large variety of compounds heterogeneous in nature and distribution and present in extremely low concentrations.

  20. Composite uranium carbide targets at TRIUMF: Development and characterization with SEM, XRD, XRF and L-edge densitometry

    NASA Astrophysics Data System (ADS)

    Kunz, Peter; Bricault, Pierre; Dombsky, Marik; Erdmann, Nicole; Hanemaayer, Vicky; Wong, John; Lützenkirchen, Klaus

    2013-09-01

    The production of radioactive ion beams (RIB) from spallation targets by irradiation with a continuous 500 MeV proton beam, has been routine at TRIUMF for several years. Based on the experience with composite refractory carbide targets a procedure for the fabrication of UC2/C targets was developed. It includes the preparation of UC2 by carbothermal reduction of UO2, the slip-casting of fine-grained UC2/C slurry on graphite foil under inert gas atmosphere and the cutting of composite target discs which are stacked up to a lamellar structure. The thermal properties of such an arrangement are adequate to withstand the high power deposition of an intense, continuous proton beam and also beneficial for the fast release of short-lived radioactive isotopes. Molecular structure, particle size and the impact of sintering of the target discs were investigated via XRD and SEM. Thickness and mass distribution were measured with position-sensitive LIII-edge densitometry. The results confirm that the properties of the UC2/C target material are well suited for RIB production at TRIUMF while there is still room for improvement with regard to uniformity of mass distribution in target disc thickness.

  1. In situ XRD study of La2Ni7H(x) during hydrogen absorption-desorption.

    PubMed

    Iwase, Kenji; Sakaki, Kouji; Nakamura, Yumiko; Akiba, Etsuo

    2013-09-01

    Structural changes of La2Ni7H(x) during the first and second absorption-desorption processes along the P-C isotherm were investigated by in situ X-ray diffraction (XRD). Orthorhombic (Pbcn) and monoclinic (C2/c) hydrides coexisted in the first absorption plateau, but only a monoclinic (C2/c) hydride was observed in the first desorption plateau. Phase transformation of La2Ni7H(x) was irreversible between the first as well as the second absorption-desorption process. The lattice parameters and expansion of the La2Ni4 and LaNi5 cells during the absorption-desorption process were refined using the Rietveld method. The lattice parameters a and b of the orthorhombic hydride (Pbcn) decreased, while the lattice parameter c increased with increasing hydrogen content in the first absorption. During the first absorption, the volume of the orthorhombic La2Ni4 cell expanded by more than 50%, while the expansion of the LaNi5 cell was below 10%. The monoclinic La2Ni4 cell expanded to approximately four times the size of the LaNi5 cell in the first absorption. The lattice parameters a, b, and c of the monoclinic hydride (C2/c) decreased with decreasing hydrogen content in the first desorption. These La2Ni4 and LaNi5 cells contracted isotropically in the first desorption. PMID:23962270

  2. Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy.

    PubMed

    Houston, Jacqueline R; Maxwell, Robert S; Carroll, Susan A

    2009-01-01

    Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (+/- 0.1) x 10(-5) s(-1) for a solution:solid of 10:1 and 1.6 (+/- 0.8) x 10(-4) s(-1) for a solution:solid of 5:1 (batch mode; T = 150 degrees C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at delta iso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (+/- 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR. PMID:19144195

  3. In-situ XRD study of the olivine - ringwoodite transformation kinetics: application for effects of water on its growth kinetics

    NASA Astrophysics Data System (ADS)

    Ning, J.; Wang, S.; Kubo, T.; Higo, Y.; Funakoshi, K.

    2012-12-01

    Dependence of water on the growth kinetics in San Carlos olivine phase transformation to ringwoodite was investigated with time-reserved X-ray diffraction method on BL04B1 station at SPring 8. The starting material is San Carlos olivine powder. Water is added by a mixture of Mg(OH)2 and SiO2. Single crystalline diamond or Ag-Pd is used as the sample capsule to prevent the escape of water. Pressure is generated by the double stage method in the SPEED 1500 system and measured by the gold pressure maker. After the annealing of the sample in the olivine stability field, we observed the olivine-ringwoodite transformation kinetics by time-reserved X-ray diffraction measurements with energy dispersive method using a solid-state detector. Kinetic data of the olivine phase transformation to ringwoodite, at about 16-20 GPa, 680-1050 C, and 500-2000 wt. ppm. H2O, were obtained. In previous kinetic studies, in-situ XRD experiments have been limited to the olivine-wadsleyite transformation. However, the kinetic data on the olivine-ringwoodite transformation is also indispensable to discuss the presence of the metastable olivine seismologically detected in some slabs. The kinetic data newly obtained here, combined with the previous published data, are used to study the effect of water on the olivine transformation to ringwoodite.. We will discuss the difference of the olivine transformation to ringwoodite and to wadsleyite, and the extent of metastable olivine in subduction zone under complicated water environment.

  4. Characterization of Recrystallization and Microstructure Evolution in Lead-Free Solder Joints Using EBSD and 3D-XRD

    NASA Astrophysics Data System (ADS)

    Zhou, Bite; Bieler, Thomas R.; Lee, Tae-Kyu; Liu, Wenjun

    2013-02-01

    Development of vulnerable high-angle grain boundaries (and cracks) from low-angle boundaries during thermal cycling by means of continuous recrystallization was examined in fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt.%) (SAC305) lead-free solder joints. Electron backscatter diffraction (EBSD) and differential-aperture x-ray microscopy (DAXM or 3D-XRD) were used for surface and subsurface characterization. A large number of subgrain boundaries were observed in the parent orientation using both techniques. However, unlike studies of anisotropic deformation in noncubic metals at much lower homologous temperatures, no streaked diffraction peaks were observed in DAXM Laue patterns within each 1 ?m3 voxel after thermal cycling, suggesting that geometrically necessary dislocations (GNDs) are effectively absorbed by the preexisting subgrain boundaries. Storage at room temperature (0.6 T m) prior to DAXM measurement may also facilitate recovery processes to reduce local GND contents. Heterogeneous residual elastic strains were found near the interface between a precipitated Cu6Sn5 particle and the Sn grain, as well as near particular subgrain boundaries in the parent orientation. Grain boundary migration associated with recrystallization resulted in regions without internal strains, subgrain boundaries, or orientation gradients. Development of new grain orientations by continuous recrystallization and subsequent primary recrystallization and grain growth occurred in the regions where the cracks developed. Orientation gradients and subgrain structure were observed within newly formed recrystallized grains that could be correlated with slip systems having high Schmid factors.

  5. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Effect of Temperature on Structural and Magnetic Properties of Laser Ablated Iron Oxide Deposited on Si(100)

    Microsoft Academic Search

    Ramay M. Shahid; Siddiqi A. Saadat; Anwar M. Sabieh; S. Shin C

    2009-01-01

    We fabricate Fe3O4 thin films on Si(100) substrates at different temperatures using pulsed laser deposition, and study the effect of annealing and deposition temperature on the structural and magnetic properties of Fe3O4 thin films. Subsequently, the films are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometery (VSM). The XRD results of these films confirm the

  6. Easy synthesis of high-purity BiFeO3 nanoparticles: new insights derived from the structural, optical, and magnetic characterization.

    PubMed

    Ortiz-Quiñonez, José Luis; Díaz, David; Zumeta-Dubé, Inti; Arriola-Santamaría, Humberto; Betancourt, Israel; Santiago-Jacinto, Patricia; Nava-Etzana, Noel

    2013-09-16

    Synthesis of high-purity BiFeO3 is very important for practical applications. This task has been very challenging for the scientific community because nonstoichiometric Bi(x)Fe(y)O(z) species typically appear as byproducts in most of the synthesis routes. In the present work, we outline the synthesis of BiFeO3 nanostructures by a combustion reaction, employing tartaric acid or glycine as promoter. When glycine is used, a porous BiFeO3 network composed of tightly assembled and sintered nanocrystallites is obtained. The origin of high purity BiFeO3 nanomaterial as well as the formation of other byproducts is explained on the basis of metal-ligand interactions. Structural, morphological, and optical analysis of the intermediate that preceded the formation of porous BiFeO3 structures was accomplished. The thorough characterization of BiFeO3 nanoparticles (NPs) included powder X-ray diffraction (XRD); scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM); thermogravimetric analysis (TGA); UV-vis electronic absorption (diffuse reflectance mode), Raman scattering, Mössbauer, and electron paramagnetic resonance (EPR) spectroscopies; and vibrating sample magnetometry (VSM). The byproducts like ?-Bi2O3 and 5 nm Bi2Fe4O9 NPs were obtained when tartaric acid was the promoter. However, no such byproducts were formed using glycine in the synthesis process. The average sizes of the crystallites for BiFeO3 were 26 and 23 nm, for tartaric acid and glycine promoters, respectively. Two band gap energies, 2.27 and 1.66 eV, were found for BiFeO3 synthesized with tartaric acid, obtained from Tauc's plots. A remarkable selective enhancement in the intensity of the BiFeO3 A1 mode, as a consequence of the resonance Raman effect, was observed and discussed for the first time in this work. For glycine-promoted BiFeO3 nanostructures, the measured magnetization (M) value at 20,000 Oe (0.64 emu g(-1)) was ?5 times lower than that obtained using tartaric acid. The difference between the M values has been associated with the different morphologies of the BiFeO3 nanostructures. PMID:23967797

  7. Influence of pH on the interlayer cationic composition and hydration state of Ca-montmorillonite: analytical chemistry, chemical modelling and XRD

    E-print Network

    Boyer, Edmond

    of nuclear waste disposal. The potential of smectite stems8 from its mechanical self-healing ability, its lowInfluence of pH on the interlayer cationic composition and hydration state of Ca composition was monitored together with the interlayer composition and X-ray diffraction (XRD) patterns were

  8. Magnetism and Magnetic Properties

    NSDL National Science Digital Library

    Roberta Schneck

    2011-10-13

    Students will identify properties of magnetism and begin to develop understanding of their practical applications. Students will also begin to develop understanding of the essential nature of Earth's magnetic fields.

  9. Structural and magnetic properties of granular Co-Pt multilayers with perpendicular magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Figueroa, A. I.; Bartolomé, J.; García, L. M.; Bartolomé, F.; Bun?u, O.; Stankiewicz, J.; Ruiz, L.; González-Calbet, J. M.; Petroff, F.; Deranlot, C.; Pascarelli, S.; Bencok, P.; Brookes, N. B.; Wilhelm, F.; Smekhova, A.; Rogalev, A.

    2014-11-01

    We present a study of granular Co-Pt multilayers by means of high-resolution transmission electron microscopy (HRTEM), extended x-ray absorption fine structure (EXAFS), SQUID-based magnetic measurements, anomalous Hall effect (AHE), and x-ray magnetic circular dichroism (XMCD). We describe these granular films as composed of particles with a pure cobalt core surrounded by an alloyed Co-Pt interface, embedded in a Pt matrix. The alloy between the Co and Pt in these granular films, prepared by room temperature sputter deposition, results from interdiffusion of the atoms. The presence of this alloy gives rise to a high perpendicular magnetic anisotropy (PMA) in the granular films, as consequence of the anisotropy of the orbital moment in the Co atoms in the alloy, and comparable to that of highly-ordered CoPt L 10 alloy films. Their magnetic properties are those of ferromagnetically coupled particles, whose coupling is strongly temperature dependent: at low temperatures, the granular sample is ferromagnetic with a high coercive field; at intermediate temperatures the granular film behaves as an amorphous asperomagnet, with a coupling between the grains mediated by the polarized Pt, and at high temperatures, the sample has a superparamagnetic behavior. The coupling/decoupling between the grains in our Co-Pt granular films can be tailored by variation of the amount of Pt in the samples.

  10. Doping effects of Co 2+ ions on structural and magnetic properties of ZnO nanoparticles

    Microsoft Academic Search

    Faheem Ahmed; Shalendra Kumar; Nishat Arshi; M. S. Anwar; Bon Heun Koo; Chan Gyu Lee

    In this paper, we report the synthesis of Zn1?xCoxO (0.0?x?0.10) nanoparticles by an auto-combustion method using glycine as a fuel. The prepared nanoparticles were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and DC magnetization measurements. XRD results showed that Co doped ZnO have a single phase nature with

  11. Effect of Si on the magnetic properties of the Fe70Al30 alloy

    Microsoft Academic Search

    G. A. Pérez Alcázar; Ligia. E. Zamora; J. D. Betancur-Ríos; J. A. Tabares; J. M. Greneche; J. M. González

    2006-01-01

    (Fe70Al30)100-xSix (x=0, 5, 10 and 20) alloys were obtained by mechanical milling for durations of 12, 24 and 36 h. They were studied by X-ray diffraction (XRD), Mössbauer spectrometry and magnetic measurements at room temperature. The XRD experiments show that all the samples have the Fe-BCC phase and for x=20 an additional Fe0.34Si0.66 phase appears. The obtained Mössbauer spectra show

  12. Effect of Si on the magnetic properties of the Fe 70Al 30 alloy

    Microsoft Academic Search

    G. A. Pérez Alcázar; Ligia. E. Zamora; J. D. Betancur-Ríos; J. A. Tabares; J. M. Greneche; J. M. González

    2006-01-01

    (Fe70Al30)100?xSix (x=0, 5, 10 and 20) alloys were obtained by mechanical milling for durations of 12, 24 and 36h. They were studied by X-ray diffraction (XRD), Mössbauer spectrometry and magnetic measurements at room temperature. The XRD experiments show that all the samples have the Fe-BCC phase and for x=20 an additional Fe0.34Si0.66 phase appears. The obtained Mössbauer spectra show a

  13. Interface charge transfer in polypyrrole coated perovskite manganite magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Pana, O.; Soran, M. L.; Leostean, C.; Macavei, S.; Gautron, E.; Teodorescu, C. M.; Gheorghe, N.; Chauvet, O.

    2012-02-01

    Different hybrid structures were obtained by coating magnetic nanoparticles of perovskite type manganite at optimal doping (La0.67Sr0.33MnO3,LSMO) with different quantities of polypyrrole (PPy). The amorphous layer of polypyrrole surrounding the crystalline magnetic core was observed by high resolution transmission electron microscopy (HRTEM) and analyzed by using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) measurements in near edge structure (XANES) techniques. By analyzing the magnetic behavior of the samples one can observe that the surface modification of magnetic nanoparticles by PPy results in an increase in the saturation magnetization of the composites. The process is ascribed to paired electrons transferred from the delocalized ? states of the PPy into the outer disordered layers of the manganite. The analysis of pre-edge peak of the Mn K-edge XANES spectra in the case of PPy coated LSMO nanoparticles indicates that the charge transfer between polymer and nanoparticles is (directed) going to missing or distorted oxygen positions, hence increasing the 3d electrons' mobility and orbital hybridization between the neighboring manganese ion. As a consequence, within the surface layers of LSMO nanoparticles, both energy bands disrupted the structure, and the double exchange process between Mn ions was reestablished determining the saturation magnetizations and pre-edge features increase, respectively.

  14. Study of the effect of Mn and Cu in Fe Mn Al C Cu alloys by ICEMS and XRD

    Microsoft Academic Search

    J. D. Betancur-Ríos; J. A. Tabares; G. A. Pérez Alcázar; V. F. Rodríguez

    2007-01-01

    Experimental analysis of magnetic and structural properties of Fe Mn Al C Cu alloys with compositions Fe x Mn0.915 - x Al0.075C0.01 (series A) and Fe x Mn0.912 - x Al0.075C0.01Cu0.003 (series B), 0.500 <= x <= 0.800, in steps of 0.050 is presented and discussed. The analysis was performed by integral conversion electrons Mössbauer spectrometry and X-ray diffraction at

  15. Synthesis and Characterization of Magnetic Metal-encapsulated Multi-walled Carbon Nanobeads

    PubMed Central

    2008-01-01

    A novel, cost-effective, easy and single-step process for the synthesis of large quantities of magnetic metal-encapsulated multi-walled carbon nanobeads (MWNB) and multi-walled carbon nanotubes (MWNT) using catalytic chemical vapour deposition of methane over Mischmetal-based AB3alloy hydride catalyst is presented. The growth mechanism of metal-encapsulated MWNB and MWNT has been discussed based on the catalytically controlled root-growth mode. These carbon nanostructures have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM and HRTEM), energy dispersive analysis of X-ray (EDAX) and thermogravimetric analysis (TGA). Magnetic properties of metal-filled nanobeads have been studied using PAR vibrating sample magnetometer up to a magnetic field of 10 kOe, and the results have been compared with those of metal-filled MWNT.

  16. Structural and Magnetic Properties of Polypyrrole Nanocomposites

    Microsoft Academic Search

    R. Turcu; I. Peter; O. Pana; L. Giurgiu; N. Aldea; B. Barz; M. N. Grecu; A. Coldea

    2004-01-01

    We report the synthesis and characterization of conducting polymer nanocomposites based on polypyrrole(PPY)and Fe2O3magnetic particles. The global structure of PPY nanocomposites was obtained by X-ray Diffraction(XRD)method using a new approximation based on Generalized Fermi Function. The local structural parameters of Fe sites in Fe2O3nanocrystallites embedded in PPY were determined by X-ray Absorption Spectroscopy(EXAFS). The lack of hysteresis loop for the

  17. Some Magnetic Properties of YTiFe Si C Carbides

    Microsoft Academic Search

    Corneliu-Bazil Cizmas; Lotfi Bessais; Catherine Djega-Mariadassou

    2008-01-01

    The effect of carbonation on the structure and the magnetic properties of polycrystalline YTiFe11-x Six (0 les x les 2) have been investigated by means of x-ray diffraction (XRD) at room temperature and magnetic measurements at low temperature. The alloys were prepared by typical induction melting and the carbonation was performed by solid-solid reaction. The cell volume of ThMn12 structure

  18. Electrodeposited CoPt thin films for magnetic hard disks

    Microsoft Academic Search

    B. Bozzini; D. de Vita; A. Sportoletti; G. Zangari; P. L. Cavallotti; E. Terrenzio

    1993-01-01

    ew baths for Co-Pt electrodeposition have been developed and developed and ECD thin films (<=0.3mum) have been prepared and characterized structurally (XRD), morphologically (SEM), chemically (EDS) and magnetically (VSM); their improved corrosion, oxidation and wear resistance have been ascertained. Such alloys appear suitable candidates for magnetic storage systems, from all technological viewpoints. The originally formulated baths contain Co-NH3-citrate complexes and

  19. Study of the effect of Mn and Cu in Fe–Mn–Al–C–Cu alloys by ICEMS and XRD

    Microsoft Academic Search

    J. D. Betancur-Ríos; J. A. Tabares; G. A. Pérez Alcázar; V. F. Rodríguez

    Experimental analysis of magnetic and structural properties of Fe–Mn–Al–C–Cu alloys with compositions Fe\\u000a x\\u000a Mn0.915???x\\u000a Al0.075C0.01 (series A) and Fe\\u000a x\\u000a Mn0.912???x\\u000a Al0.075C0.01Cu0.003 (series B), 0.500???x???0.800, in steps of 0.050 is presented and discussed. The analysis was performed by integral conversion electrons Mössbauer\\u000a spectrometry and X-ray diffraction at room temperature. The results suggest, for both series of alloys, that for

  20. Study of the effect of Mn and Cu in Fe–Mn–Al–C–Cu alloys by ICEMS and XRD

    Microsoft Academic Search

    J. D. Betancur-Ríos; J. A. Tabares; G. A. Pérez Alcázar; V. F. Rodríguez

    2007-01-01

    Experimental analysis of magnetic and structural properties of Fe–Mn–Al–C–Cu alloys with compositions Fe\\u000a x\\u000a Mn0.915???x\\u000a Al0.075C0.01 (series A) and Fe\\u000a x\\u000a Mn0.912???x\\u000a Al0.075C0.01Cu0.003 (series B), 0.500???x???0.800, in steps of 0.050 is presented and discussed. The analysis was performed by integral conversion electrons Mössbauer\\u000a spectrometry and X-ray diffraction at room temperature. The results suggest, for both series of alloys, that for

  1. Combining µXANES and µXRD mapping to analyse the heterogeneity in calcium carbonate granules excreted by the earthworm Lumbricus terrestris

    PubMed Central

    Brinza, Loredana; Schofield, Paul F.; Hodson, Mark E.; Weller, Sophie; Ignatyev, Konstantin; Geraki, Kalotina; Quinn, Paul D.; Mosselmans, J. Frederick W.

    2014-01-01

    The use of fluorescence full spectral micro-X-ray absorption near-edge structure (µXANES) mapping is becoming more widespread in the hard energy regime. This experimental method using the Ca K-edge combined with micro-X-ray diffraction (µXRD) mapping of the same sample has been enabled on beamline I18 at Diamond Light Source. This combined approach has been used to probe both long- and short-range order in calcium carbonate granules produced by the earthworm Lumbricus terrestris. In granules produced by earthworms cultured in a control artificial soil, calcite and vaterite are observed in the granules. However, granules produced by earthworms cultivated in the same artificial soil amended with 500?p.p.m. Mg also contain an aragonite. The two techniques, µXRD and µXANES, probe different sample volumes but there is good agreement in the phase maps produced. PMID:24365942

  2. Quantitative assessment of alkali-reactive aggregate mineral content through XRD using polished sections as a supplementary tool to RILEM AAR-1 (petrographic method)

    SciTech Connect

    Castro, Nelia, E-mail: nelia.castro@ntnu.no [Norwegian University of Science and Technology (NTNU), Department of Geology and Mineral Resources Engineering, Sem Saelands vei 1, N-7491 Trondheim (Norway)] [Norwegian University of Science and Technology (NTNU), Department of Geology and Mineral Resources Engineering, Sem Saelands vei 1, N-7491 Trondheim (Norway); Sorensen, Bjorn E. [Norwegian University of Science and Technology (NTNU), Department of Geology and Mineral Resources Engineering, Sem Saelands vei 1, N-7491 Trondheim (Norway)] [Norwegian University of Science and Technology (NTNU), Department of Geology and Mineral Resources Engineering, Sem Saelands vei 1, N-7491 Trondheim (Norway); Broekmans, Maarten A.T.M. [Geological Survey of Norway, Department of Industrial Minerals and Metals, PO Box 6315 Sluppen, N-7491 Trondheim (Norway)

    2012-11-15

    The mineral content of 5 aggregate samples from 4 different countries, including reactive and non-reactive aggregate types, was assessed quantitatively by X-ray diffraction (XRD) using polished sections. Additionally, electron probe microanalyzer (EPMA) mapping and cathodoluminescence (CL) were used to characterize the opal-CT identified in one of the aggregate samples. Critical review of results from polished sections against traditionally powdered specimen has demonstrated that for fine-grained rocks without preferred orientation the assessment of mineral content by XRD using polished sections may represent an advantage over traditional powder specimens. Comparison of data on mineral content and silica speciation with expansion data from PARTNER project confirmed that the presence of opal-CT plays an important role in the reactivity of one of the studied aggregates. Used as a complementary tool to RILEM AAR-1, the methodology suggested in this paper has the potential to improve the strength of the petrographic method.

  3. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system. Part 1: Ca-Sr-Cu oxides

    Microsoft Academic Search

    B. J. Reardon; C. R. Hubbard

    1992-01-01

    X-ray powder patterns for the phases in the CaO-SrO-CuO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a simulated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here

  4. A Chemical, XRD, and 27Al MAS NMR Investigation of Miocene Gulf Coast Shales with Application to Understanding Illite\\/Smectite Crystal-Chemistry

    Microsoft Academic Search

    Paul A. Schroeder

    1993-01-01

    This study assesses the distribution of A1 and Fe in mixed-layer illite\\/smectites (I\\/S) in shales undergoing burial diagenetic changes, using evidence from 27A1 NMR, XRD, and chemical analyses. Samples studied include a sequence of mixed-layer I\\/S (ranging from 40% to 68% illite layers) in shales from a well located in the Caillou Island Oil Field, Terrebonne Parish, Louisiana, as well

  5. FT-IR and XRD characterization of phase transformation of heat-treated synthetic natisite (Na 2TiOSiO 4) powder

    Microsoft Academic Search

    Gow-Weng Peng; Hok-Shing Liu

    1995-01-01

    A sodium titanium silicate polycrystalline powder, natisite (Na2TiOSiO4), has been prepared by a hydrothermal process and heat-treated between 800 and 1500 °C. The phase transformation of natisite has been evaluated by using absorption infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy\\/energy-dispersive spectrometry (SEM\\/ EDS) techniques. The sequence of phase transformation may be divided

  6. 2,4-Dichlorophenoxyacetic acid (2,4-D) photodegradation using an M n+ \\/ZrO 2 photocatalyst: XPS, UV–vis, XRD characterization

    Microsoft Academic Search

    M. Alvarez; T. López; J. A. Odriozola; M. A. Centeno; M. I. Domínguez; M. Montes; P. Quintana; D. H. Aguilar; R. D. González

    2007-01-01

    Zirconium oxide materials doped with transition metals (Mn, Fe, Co, Ni and Cu) were synthesized using sol–gel methods. The powders, which were obtained, were characterized by XPS, XRD, UV–vis spectroscopy and nitrogen adsorption.The photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D), a herbicide used in agricultural applications, was used as a test reaction to study the activity of the compounds synthesized. Photodegradation studies

  7. XANES, Raman and XRD study of anthracene-based cokes and saccharose-based chars submitted to high-temperature pyrolysis

    Microsoft Academic Search

    S. Bernard; O. Beyssac; K. Benzerara; N. Findling; G. Tzvetkov; G. E. Brown Jr.

    2010-01-01

    Graphitizing anthracene-based cokes and non-graphitizing saccharose-based chars were processed at temperatures from 450°C to 2900°C at ambient pressure. This offers a whole set of samples that greatly differ in structure. Here, their structural evolution was monitored by combining XRD and visible (green) Raman spectroscopy as well as, for the first time, near-infrared Raman and synchrotron-based C-XANES spectroscopies. These different techniques

  8. Microstructure of multistage annealed nanocrystalline SmCo{sub 2}Fe{sub 2}B alloy with enhanced magnetic properties

    SciTech Connect

    Jiang, Xiujuan, E-mail: xiujuan.jiang@Huskers.unl.edu; Shield, Jeffrey E. [Department of Mechanical and Materials Engineering, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States); Devaraj, Arun [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States); Balamurugan, B. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States); Cui, Jun [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States)

    2014-02-14

    The microstructure and chemistry of SmCo{sub 2}Fe{sub 2}B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe){sub 4}B (1:4:1) and Sm{sub 2}(Co,Fe){sub 17}B{sub x} (2:17:x) magnetic phases were confirmed using both techniques. Fe{sub 2}B at a scale of ?5?nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

  9. Characterization of quenched high pressure phases in CaSiO sub 3 system by XRD and sup 29 Si NMR

    SciTech Connect

    Kanzaki, Masami (Univ. of Alberta, Edmonton (Canada)); Stebbins, J.F.; Xianyu Xue (Stanford Univ., CA (United States))

    1991-03-01

    The authors have studied quenched high pressure phases in the CaSiO{sub 3} system by x-ray diffraction (XRD) and {sup 29}Si MAS NMR. XRD study of the previously reported {var epsilon}-CaSiO{sub 3}' phase synthesized at 12 GPa and 1,500C reveals that it is actually a mixture of {beta}-Ca{sub 2}SiO{sub 4} (larnite) and a previously unknown CaSi{sub 2}O{sub 5} phase. This result is supported by the {sup 29}Si NMR spectra. Furthermore, both the XRD and the NMR data suggest that the CaSi{sub 2}O{sub 5} phase may have a titanite (CaTiSiO{sub 5}) structure in which Ti is replaced by an octahedral Si. Samples quenched from 15 GPa and 1,500C consist mostly of an amorphous phase, but a small amount of CaSiO{sub 3}-perovskite was identified by both XRDE and NMR. The {sup 29}Si NMR spectrum of the amorphous phase suggests that its local structure is similar to that of a glass quenched from melt at 1 bar.

  10. X-ray diffraction microtomography (XRD-CT), a novel tool for non-invasive mapping of phase development in cement materials.

    PubMed

    Artioli, G; Cerulli, T; Cruciani, G; Dalconi, M C; Ferrari, G; Parisatto, M; Rack, A; Tucoulou, R

    2010-07-01

    A recently developed synchrotron-based imaging technique, X-ray diffraction microtomography (XRD-CT), has been applied here for the first time to a complex system, the hydrating Portland cement paste, in order to monitor the evolution of microstructure and phase formation with a 3D non-invasive imaging approach. The ettringite-XRD-peak-based image reconstructions, combined with transmission microtomography (X-microCT) images, allowed to assess the ubiquitous distribution of this phase, which appears early in the hydration process and showed its preferential concentration in the relatively less compact regions of the paste. The comparison of greyscale histograms for cement pastes after 9 and 58 h from hydration showed an increase of ettringite content with age, in agreement with the quantitative Rietveld analysis of the sum patterns. By renormalizing the greyscale histograms to the relative weight fraction, as obtained from Rietveld refinements, a new technique which allows estimation of phase contents with spatial resolution has been developed. The results achievable by combining XRD-CT, X-microCT and Rietveld appear very promising to provide experimental snapshots of the cement hydration process to be compared with results obtained from computer simulations. PMID:20358183

  11. Characterizing the Phyllosilicates and Amorphous Phases Found by MSL Using Laboratory XRD and EGA Measurements of Natural and Synthetic Materials (Invited)

    NASA Astrophysics Data System (ADS)

    Rampe, E. B.; Morris, R. V.; Chipera, S.; Bish, D. L.; Bristow, T.; Archer, P. D.; Blake, D.; Achilles, C.; Ming, D. W.; Vaniman, D.; Crisp, J. A.; Des Marais, D. J.; Downs, R.; Farmer, J. D.; Morookian, J.; Morrison, S.; Sarrazin, P.; Spanovich, N.; Treiman, A. H.; Yen, A. S.; Team, M.

    2013-12-01

    The Curiosity Rover landed on the Peace Vallis alluvial fan in Gale crater on August 5, 2012. A primary mission science objective is to search for past habitable environments, and, in particular, to assess the role of past water. Identifying the minerals and mineraloids that result from aqueous alteration at Gale crater is essential for understanding past aqueous processes at the MSL landing site and hence for interpreting the site's potential habitability. X-ray diffraction (XRD) data from the CheMin instrument and evolved gas analyses (EGA) from the SAM instrument have helped the MSL science team identify phases that resulted from aqueous processes: phyllosilicates and amorphous phases were measure in two drill samples (John Klein and Cumberland) obtained from the Sheepbed Member, Yellowknife Bay Fm., which is believed to represent a fluvial-lacustrine environment. A third set of analyses was obtained from scoop samples from the Rocknest sand shadow. Chemical data from the APXS instrument have helped constrain the chemical compositions of these secondary phases and suggest that the phyllosilicate component is Mg-enriched and the amorphous component is Fe-enriched, relatively Si-poor, and S- and H-bearing. To refine the phyllosilicate and amorphous components in the samples measured by MSL, we measured XRD and EGA data for a variety of relevant natural terrestrial phyllosilicates and synthetic mineraloids in laboratory testbeds of the CheMin and SAM instruments. Specifically, Mg-saturated smectites and vermiculites were measured with XRD at low relative humidity to understand the behavior of the 001 reflections under Mars-like conditions. Our laboratory XRD measurements suggest that interlayer cation composition affects the hydration state of swelling clays at low RH and, thus, the 001 peak positions. XRD patterns of synthetic amorphous materials, including allophane, ferrihydrite, and hisingerite were used in full-pattern fitting (FULLPAT) models to help determine the types and abundances of amorphous phases in the martian rocks and sand shadow. These models suggest that the rocks and sand shadow are composed of ~30% amorphous phases. Sulfate-adsorbed allophane and ferrihydrite were measured by EGA to further understand the speciation of the sulfur present in the amorphous component. These data indicate that sulfate adsorbed onto the surfaces of amorphous phases could explain a portion of the SO2 evolution in the Rocknest SAM data. The additional constraints placed on the mineralogy and chemistry of the aqueous alteration phases through our laboratory measurements can help us better understand the nature of the fluids that affected the different samples and devise a history of aqueous alteration for the Sheepbed Member of the Yellowknife Bay Fm. at Gale crater.

  12. Study of the effect of Mn and Cu in Fe Mn Al C Cu alloys by ICEMS and XRD

    NASA Astrophysics Data System (ADS)

    Betancur-Ríos, J. D.; Tabares, J. A.; Pérez Alcázar, G. A.; Rodríguez, V. F.

    2007-02-01

    Experimental analysis of magnetic and structural properties of Fe Mn Al C Cu alloys with compositions Fe x Mn0.915 - x Al0.075C0.01 (series A) and Fe x Mn0.912 - x Al0.075C0.01Cu0.003 (series B), 0.500 ? x ? 0.800, in steps of 0.050 is presented and discussed. The analysis was performed by integral conversion electrons Mössbauer spectrometry and X-ray diffraction at room temperature. The results suggest, for both series of alloys, that for the highest Mn content, samples exhibit an antiferromagnetic behavior, typical of the FCC or austenite FeMn phase rich in Mn; for those of low Mn content, the coexistence of paramagnetic austenite, typical of the FeMn alloy poor in Mn, a ferromagnetic BCC or ferrite phases can be observed, while for the lowest Mn content, only ferromagnetic (FM) phase tends to prevail. The FM phase is associated to the BCC FeMnAl as was corroborated by X-ray diffraction. The samples with the highest Mn content, the influence of Cu addition is to reduce the mean hyperfine field and to stabilize the antiferromagnetic behavior.

  13. Effects of iron-based additives in the preparation of magnetic coal-based activated carbon

    Microsoft Academic Search

    Jun Zhang; Qiang Xie; Xi Chen; Juan Liu; Xin Yao

    2011-01-01

    Magnetization of activated carbon is one of the promising ways for separation of spent activated carbon from contaminants and regeneration. Magnetic coal-based activated carbons(MAC) were prepared from Taixi anthracite in the presence of Fe3O4, Fe2(C2O4)3 and Fe(NO3)3 respectively. The magnetic activated carbon samples were characterized by vibrating sample magnetometer (VSM), X-ray diffraction (XRD), N2 adsorption and scanning electric microscope (SEM).

  14. Affinity Adsorption of Bromelain on Reactive Red 120 Immobilized Magnetic Composite Particles

    Microsoft Academic Search

    Ming-Min Song; Hua-Li Nie; Yu-Ting Zhou; Li-Min Zhu; Jin-Yue Bao

    2011-01-01

    A magnetic dye affinity adsorbent was prepared by coating the magnetic nanoparticles (MNPs) with chitosan (CS), which significantly decreased the non-specifically adsorbing protein. Following this, Reactive Red 120 (Red 120), chosen as a dye affinity ligand, was immobilized onto the chitosan-coated magnetic nanoparticles (CS-MNPs) to obtain the specific protein adsorption. The prepared functionalized adsorbents were characterized by SEM, FTIR, XRD,

  15. Controlled oxidation of FeCo magnetic nanoparticles to produce faceted FeCo/ferrite nanocomposites for rf heating applications

    E-print Network

    Laughlin, David E.

    Controlled oxidation of FeCo magnetic nanoparticles to produce faceted FeCo/ferrite nanocomposites for polydisperse FeCo magnetic nanoparticles MNPs synthesized using an induction plasma torch. X-ray diffraction to promote oxidation and XRD was used to follow the evolution of the FeCo core and the Fe3O4 and FeO oxide

  16. Electronic and magnetic properties of Co-doped ZnO diluted magnetic semiconductor

    Microsoft Academic Search

    R. K. Singhal; Arvind Samariya; Y. T. Xing; Sudhish Kumar; S. N. Dolia; U. P. Deshpande; T. Shripathi; Elisa B. Saitovitch

    2010-01-01

    The effect of low level Co doping (5%) on polycrystalline ZnO samples has been investigated to correlate the observed changes in their magnetic state vis à vis changes in their electronic properties. Rietveld refinement of the XRD patterns confirms single phase crystallization of the samples in the wurtzite type lattice, with no evidence of any secondary phases. The as-synthesized Co-doped

  17. Magnetic Properties of Nanocrystalline Nickel-Cobalt Ferrites

    NASA Astrophysics Data System (ADS)

    Tiwari, D. K.; Villaseñor-Cendejas, L. M.; Thakur, A. K.

    2013-09-01

    In this study, the nanocrystalline nickel-cobalt ferrites were prepared via the citrate route method at . The samples were calcined at for 3 h. The crystalline structure and the single-phase formations were confirmed by X-ray diffraction (XRD) measurements. Prepared materials showed the cubic spinel structure with m3m symmetry and Fd3m space group. The analyses of XRD patterns were carried out using POWD software. It gave an estimation of lattice constant “” of 8.3584 Å, which was in good agreement with the results reported in JCPDS file no. 742081. The crystal size of the prepared materials calculated by Scherer’s formula was 27.6 nm and the electrical conductivity was around . The permeability component variations with frequency were realized. The magnetic properties of the prepared materials were analyzed by a vibrating sample magnetometer (VSM). It showed a saturation magnetization of and the behavior of a hard magnet.

  18. Nanostructure and magnetic properties of Ni-substituted finemet ribbons

    NASA Astrophysics Data System (ADS)

    Iturriza, N.; Fernández, L.; Ipatov, M.; Vara, G.; Pierna, A. R.; del Val, J. J.; Chizhik, A.; González, J.

    2007-09-01

    Magnetic anisotropy has been induced during the nanocrystallization process of Ni-rich amorphous ferromagnetic ( Finemet) ribbons by means of the application of a constant stress during the annealing process. Magnetization measurements have evidenced the anisotropy of the treated samples. The main goal of this work was the analysis of the treated ribbons using X-ray Diffraction (XRD), Transmission Electronic Microscopy (TEM) and Atomic Force Microscopy (AFM). AFM measurements revealed in all the cases a strong nanocrystallisation of the surface without evidences of amorphous matrix, which contrast with XRD and TEM measurements that have shown a high content of amorphous phase in the bulk of the ribbons. Magneto-optical Kerr effect measurements show much higher coercive field values than in the bulk, indicating a complex magnetic behavior for the surface of the ribbons.

  19. Electrochemical fabrication of nanocomposite films containing magnetic metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Hayashi, Yoshiaki; Hashi, Shuichiro; Kura, Hiroaki; Yanai, Takeshi; Ogawa, Tomoyuki; Ishiyama, Kazushi; Nakano, Masaki; Fukunaga, Hirotoshi

    2015-07-01

    Controlling the structure composed of soft and hard magnetic phases at the nanoscale is the key to fabricating nanocomposite magnets with efficient exchange coupling. In our previous study, nanocomposite films containing ferrite nanoparticles were fabricated by a combination of electrophoretic deposition and electroplating to show one possibility of controlling the structure of nanocomposite magnets three-dimensionally by applying self-assembly of magnetic nanoparticles. To expand this combination method to the fabrication of nanocomposite magnets, the use of magnetic metal nanoparticles is desired. In this paper, we attempted to fabricate nanocomposite films composed of Fe–Co nanoparticles in a Fe–Pt matrix by this combination method. Through cross-sectional observation and XRD analysis, a nanostructure composed of Fe–Co nanoparticles embedded in a L10 Fe–Pt matrix was confirmed. These results indicate that this method is capable of producing composite materials containing metal magnetic nanoparticles.

  20. Effect of deposition pressure on the structural and magnetic properties of cobalt ferrite thin films

    SciTech Connect

    Nongjai, R.; Khan, S.; Ahmad, H.; Khan, I. [Department of Applied Physics, Zakir Hussain College of Engineering and Technology, A.M.U., Aligarh (India); Asokan, K. [Material Science Division, Inter University Accelerator Centre, New Delhi (India)

    2013-06-03

    We present the influence of deposition pressure on the structural and magnetic properties of cobalt ferrite thin films. Thin films of Co ferrite were deposited by rf sputtering on Si (100) substrate and characterized by X - Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Vibrating Sample Magnetometer (VSM). The XRD patterns showed the formation of crystalline single phase of the films. The particle size and surface roughness of the films were strongly influence by gas pressure. Hysteresis loops measured at room temperature showed the enhancement of magnetic properties with the increase of gas pressure which is attributed to the decrease of particle size.

  1. A rock magnetic study on red palaeosols in Yun-Gui Plateau (Southwestern China) and evidence for uplift of Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Siyuan; Lu, Shenggao

    2014-02-01

    Magnetic signals of red palaeosols from the Yun-Gui Plateau (YGP), southwestern China, are studied using rock magnetism, selective chemical dissolution, differential X-ray diffraction (DXRD) and high-resolution transmission electron microscopy (HRTEM) in order to explore the potential of red palaeosol as a proxy indicator of paleogenesis and uplift of plateau. Red palaesols are characterized by highly magnetic signals and dark red color with a hue of 5 YR (yellow-red). The low-frequency magnetic susceptibility (?lf) of topsoils is shown to vary from 1500 × 10-8 to 2500 × 10-8m3 kg-1 in a decreasing pattern from the top to bottom of the profile. Magnetic profiles reveal that the red palaeosols contain significant amount of fine-grained superparamagnetic (SP) grains, which is attributed to the higher concentration of pedogenic SP maghemite. The dithionite-citrate-bicarbonate (DCB) procedure can selectively dissolve ultrafine pedogenic magnetic minerals in the red palaeosols, as evidenced by the highly correlation between mass-specific frequency-dependent magnetic susceptibility (?fd) and ?lf loss of DCB treatment. The magnetic loss after DCB treatment accounts for 87-95 per cent of the original susceptibility. Rock magnetism and DXRD reveal that the main magnetic mineral in the red palaeosols is the pedogenic SP/stable single domain (SP/SSD) maghemite. These pedogenic maghemites account for about 1 per cent of free iron oxides. HRTEM observations show the evidence of pedogenic SP (<˜20-30 nm) and pure maghemite. These magnetic particles vary from several to tens of nanometres in size and exhibit typical crystallochemical characteristics of this mineral. Magnetic evidence suggests that the red palaeosols experience a strongly pedogenic processes. Pedogenic processes result in the neoformation of hematite and maghemite, and causes a substantial increase in the magnetic susceptibility and other magnetic signals. Therefore, the rock magnetism of red palaeosols potentially yields significant palaeopedogenic information and evidence on the neotectonic movement of plateau. Results of the present work suggest that the red palaeosols could be a good tool for understanding the amplitude and the age of uplift in the YGP.

  2. PyXRD v0.6.2: a FOSS program to quantify disordered, layered minerals using multi-specimen X-ray diffraction profile fitting

    NASA Astrophysics Data System (ADS)

    Dumon, M.; Van Ranst, E.

    2015-03-01

    This paper presents a free and open-source model called PyXRD (short for Python X-ray diffraction) to improve the quantification of complex, poly-phasic mixed-layer phyllosilicate assemblages. The novelty of this model is the ab initio incorporation of the multi-specimen method, making it possible to share phases and (a selection of) their parameters across multiple specimens. By effectively reducing the number of parameters and increasing the number of observations, this approach speeds up the manual refinement process significantly when automated algorithms are used. To check the hypothesis that the multi-specimen set-up can improve automatic parameter refinement, we calculated X-ray diffraction patterns for four theoretical mineral assemblages. These patterns were then used as input for a refinement employing the multi-specimen set-up and one employing the single-pattern set-ups. For all of the assemblages, PyXRD was able to reproduce or approximate the input parameters with the multi-specimen approach. Diverging solutions only occurred in single-pattern set-ups which do not contain enough information (e.g. patterns of heated samples) to discern all the different minerals. Assuming a correct qualitative interpretation was made and a single pattern exists in which all phases are sufficiently discernible, the obtained results indicate a good quantification can often be obtained with just that pattern. For naturally occurring samples, this could mean modelling air-dry and/or ethylene-glycolated patterns might be sufficient. However, these results from theoretical experiments cannot automatically be extrapolated to all real-life experiments. In any case, PyXRD has proven to be very useful when X-ray diffraction patterns are modelled for complex mineral assemblages containing mixed-layer phyllosilicates with a multi-specimen approach.

  3. XRD and xanes studies of copper complexes using (diethyl 4-amino-1-phenyl-1H-pyrazole-3,5 dicarboxylate) as ligand

    NASA Astrophysics Data System (ADS)

    Mishra, Ashutosh; Jain, Garima

    2013-06-01

    X-ray diffraction (XRD) and X-ray absorption spectroscopic (XAS) studies have been done on three copper complexes using (diethyl 4-amino-1-phenyl-1H-pyrazole-3,5 dicarboxylate) as ligand. The X-ray diffraction studies of copper complexes have been recorded using Rigaku RINT-2000 X-ray diffractometer equipped with a rotating anode with tube voltage of 40 kV and current of 100 mA. The X-ray absorption spectra of the complexes have been recorded at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore and is called beamline.

  4. Effect of interparticle interactions on size determination of zirconia and silica based systems – A comparison of SAXS, DLS, BET, XRD and TEM

    PubMed Central

    Pabisch, Silvia; Feichtenschlager, Bernhard; Kickelbick, Guido; Peterlik, Herwig

    2012-01-01

    The aim of this work is a systematic comparison of size characterisation methods for two completely different model systems of oxide nanoparticles, i.e. amorphous spherical silica and anisotropic facet-shaped crystalline zirconia. Size and/or size distribution were determined in a wide range from 5 to 70 nm using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), nitrogen sorption (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM). A nearly perfect coincidence was observed only for SAXS and TEM for both types of particles. For zirconia nanoparticles considerable differences between different measurement methods were observed. PMID:22347721

  5. Galvanostatic charge-discharge tests, 57Fe and 119Sn Mössbauer and XRD measurements on novel Sn-Ni-Fe electrodeposits

    NASA Astrophysics Data System (ADS)

    Lak, G. B.; Kuzmann, E.; El-Sharif, M.; Chisholm, C. U.; Stichleutner, S.; Homonnay, Z.; Sziráki, L.

    2013-04-01

    Novel Sn-Ni-Fe ternary alloys were successfully deposited by pulse plating technique from an electrolyte based on sodium gluconate which acts as a complexing agent. XRD results revealed the predominantly amorphous character for the majority of the deposits. 57Fe and 119Sn conversion electron Mössbauer spectroscopy indicated the formation of a paramagnetic amorphous alloy using a short on-pulse duration and where the Fe content was less than 22 wt.%. Galvanostatic charge-discharge tests of the novel Sn-Ni-Fe deposits were carried out in a model Li-ion cell and indicated that the Sn-Ni-Fe alloys have potential as an electrode material.

  6. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system. Part 2, Ca-Sr-Pb oxides

    SciTech Connect

    Reardon, B.J.; Hubbard, C.R.

    1992-02-01

    X-ray powder patterns for the phases in the CaO-SrO-PbO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a calculated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca,Sr){sub 2}PbO{sub 4} solid solution series and are recommended for the PDF.

  7. Magnetic Pendulum

    NSDL National Science Digital Library

    COSI

    2009-01-01

    In this activity about magnetism (page 15 of the PDF), learners will explore how opposite and similar magnetic poles affect a swinging (pendulum) magnet. Learners will see firsthand how gravity and magnetism can work together to create a chaotic system. This is an excellent activity for experimenting with different variables to see how they affect the overall movement of a magnet.

  8. Specialty magnets

    SciTech Connect

    Halbach, K.

    1986-07-01

    A number of basic conceptual designs are explained for magnet systems that use permanent magnet materials. Included are iron free multipoles and hybrid magnets. Also appended is a discussion of the manufacturing process and magnetic properties of some permanent magnet materials. (LEW)

  9. Transmission electron microscopy and ab initio calculations to relate interfacial intermixing and the magnetism of core/shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Chi, C.-C.; Hsiao, C.-H.; Skoropata, E.; van Lierop, J.; Ouyang, Chuenhou Hao

    2015-05-01

    Significant efforts towards understanding bi-magnetic core-shell nanoparticles are underway currently as they provide a pathway towards properties unavailable with single-phased systems. Recently, we have demonstrated that the magnetism of ?-Fe2O3/CoO core-shell nanoparticles, in particular, at high temperatures, originates essentially from an interfacial doped iron-oxide layer that is formed by the migration of Co2+ from the CoO shell into the surface layers of the ?-Fe2O3 core [Skoropata et al., Phys. Rev. B 89, 024410 (2014)]. To examine directly the nature of the intermixed layer, we have used high-resolution transmission electron microscopy (HRTEM) and first-principles calculations to examine the impact of the core-shell intermixing at the atomic level. By analyzing the HRTEM images and energy dispersive spectra, the level and nature of intermixing was confirmed, mainly as doping of Co into the octahedral site vacancies of ?-Fe2O3. The average Co doping depths for different processing temperatures (150 °C and 235 °C) were 0.56 nm and 0.78 nm (determined to within 5% through simulation), respectively, establishing that the amount of core-shell intermixing can be altered purposefully with an appropriate change in synthesis conditions. Through first-principles calculations, we find that the intermixing phase of ?-Fe2O3 with Co doping is ferromagnetic, with even higher magnetization as compared to that of pure ?-Fe2O3. In addition, we show that Co doping into different octahedral sites can cause different magnetizations. This was reflected in a change in overall nanoparticle magnetization, where we observed a 25% reduction in magnetization for the 235 °C versus the 150 °C sample, despite a thicker intermixed layer.

  10. Magnetic Attraction

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students complete a series of six short investigations involving magnets to learn more about their properties. Students also discuss engineering uses for magnets and brainstorm examples of magnets in use in their everyday lives.

  11. MAGNETIC IMAGING OF NANOCOMPOSITE MAGNETS

    Microsoft Academic Search

    V. V. ZHU

    2003-01-01

    Understanding the structure and magnetic behavior is crucial for optimization of nanocomposite magnets with high magnetic energy products. Many contributing factors such as phase composition, grain size distribution and specific domain configurations reflect a fine balance of magnetic energies at nanometer scale. For instance, magnetocrystalline anisotropy of grains and their orientations, degree of exchange coupling of magnetically soft and hard

  12. A new magnetic expanded graphite for removal of oil leakage.

    PubMed

    Ding, Xiaohui; Wang, Rong; Zhang, Xin; Zhang, Yanzong; Deng, Shihuai; Shen, Fei; Zhang, Xiaohong; Xiao, Hong; Wang, Lilin

    2014-04-15

    Magnetic expanded graphite (MEG) was prepared using the blended calcination method under a nitrogen atmosphere. MEG was characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and vibrating sample magnetization (VSM). Results show that the cobalt ferrite nanoparticles were uniformly and efficiently deposited on expanded graphite (EG). The saturation magnetization reached 55.05 emu g(-1), and the adsorption capacity of MEG under the optimal condition was 35.72 g g(-1) for crude oil. PMID:24559739

  13. Magnetic Properties of Cd Substituted Ni-Cu Ferrites

    NASA Astrophysics Data System (ADS)

    Belavi, P. B.; Chavan, G. N.; Bammannavar, B. K.; Naik, L. R.; Kotnala, R. K.

    2011-07-01

    Cadmium substituted Ni-Cu Ferrites with the general formula Ni0.95-xCdxCu0.05Fe2O4 (x = 0.1, 0.2 and 0.3) were prepared by the standard double sintering ceramic method. The existences of single phase formation with crystalline size of 25-38 nm were confirmed from XRD measurements. The magnetic properties such as saturation magnetization (Ms) and Magnetic moment (?B) were studied by VSM analysis. The existence of multidomain (MD) particles in the samples was revealed from the small values of Mr/Ms.

  14. Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO{sub 4}:Dy TL material

    SciTech Connect

    Kamarudin, Nadira [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor, Malaysia and Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor (Malaysia); Abdullah, Wan Saffiey Wan; Dollah, Mohd Taufik [Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor (Malaysia); Hamid, Muhammad Azmi Abdul [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor (Malaysia)

    2014-09-03

    This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO{sub 4}) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 ?m in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO{sub 4} with average crystallite size of 74 nm with orthorhombic crystal system. The TL behavior of produced CaSO{sub 4}:Dy was studied using a TLD reader after exposure to gamma ray by Co{sup 60} source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry.

  15. Synthesis, structural and vibrational investigation on 2-phenyl-N-(pyrazin-2-yl)acetamide combining XRD diffraction, FT-IR and NMR spectroscopies with DFT calculations

    NASA Astrophysics Data System (ADS)

    Lukose, Jilu; Yohannan Panicker, C.; Nayak, Prakash S.; Narayana, B.; Sarojini, B. K.; Van Alsenoy, C.; Al-Saadi, Abdulaziz A.

    2015-01-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-phenyl-N-(pyrazin-2-yl)acetamide have been investigated experimentally and theoretically using Gaussian09 software package. The title compound was optimized by using the HF/6-31G(6D,7F) and B3LYP/6-31G(6D,7F) calculations. The geometrical parameters are in agreement with the XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital 1H-NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was performed by the DFT method. First hyperpolarizability is calculated in order to find its role in non linear optics. From the XRD data, in the crystal, molecules are held together by strong Csbnd H⋯O and Nsbnd H⋯O intermolecular interactions.

  16. In-situ investigation of stress conditions during expansion of bare metal stents and PLLA-coated stents using the XRD sin(2)?-technique.

    PubMed

    Kowalski, Wolfgang; Dammer, Markus; Bakczewitz, Frank; Schmitz, Klaus-Peter; Grabow, Niels; Kessler, Olaf

    2015-09-01

    Drug eluting stents (DES) consist of platform, coating and drug. The platform often is a balloon-expandable bare metal stent made of the CoCr alloy L-605 or stainless steel 316L. The function of the coating, typically a permanent polymer, is to hold and release the drug, which should improve therapeutic outcome. Before implantation, DES are compressed (crimped) to allow implantation in the human body. During implantation, DES are expanded by balloon inflation. Crimping, as well as expansion, causes high stresses and high strains locally in the DES struts, as well as in the polymer coating. These stresses and strains are important design criteria of DES. Usually, they are calculated numerically by finite element analysis (FEA), but experimental results for validation are hardly available. In this work, the X-ray diffraction (XRD) sin(2)?-technique is applied to in-situ determination of stress conditions of bare metal L-605 stents, and Poly-(L-lactide) (PLLA) coated stents. This provides a realistic characterization of the near-surface stress state and a validation option of the numerical FEA. XRD-results from terminal stent struts of the bare metal stent show an increasing compressive load stress in tangential direction with increasing stent expansion. These findings correlate with numerical FEA results. The PLLA-coating also bears increasing compressive load stress during expansion. PMID:25974098

  17. Synthesis, structural and vibrational investigation on 2-phenyl-N-(pyrazin-2-yl)acetamide combining XRD diffraction, FT-IR and NMR spectroscopies with DFT calculations.

    PubMed

    Lukose, Jilu; Yohannan Panicker, C; Nayak, Prakash S; Narayana, B; Sarojini, B K; Van Alsenoy, C; Al-Saadi, Abdulaziz A

    2015-01-25

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-phenyl-N-(pyrazin-2-yl)acetamide have been investigated experimentally and theoretically using Gaussian09 software package. The title compound was optimized by using the HF/6-31G(6D,7F) and B3LYP/6-31G(6D,7F) calculations. The geometrical parameters are in agreement with the XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Gauge-including atomic orbital (1)H-NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was performed by the DFT method. First hyperpolarizability is calculated in order to find its role in non linear optics. From the XRD data, in the crystal, molecules are held together by strong C-H?O and N-H?O intermolecular interactions. PMID:25124846

  18. Solid 7Li-NMR and in situ XRD studies of the insertion reaction of lithium with tin oxide and tin-based amorphous composite oxide

    NASA Astrophysics Data System (ADS)

    Furuya, Kazuhiko; Ogawa, Keizou; Mineo, Yasushi; Matsufuji, Akihiro; Okuda, Jun; Erata, Tomoki

    2001-04-01

    The lithium insertion reactions with tin (II) oxide (SnO) and tin-based composite oxide (abbreviated as TBCO) are studied by solid 7Li-NMR Knight shift, T1 and T1? relaxation rate, TEM and in situ XRD methods. By the insertion reaction for SnO, the lithium oxide and ?-tin are produced first at Li/Sn = 2; at Li/Sn = 3 to 6 the products are not simple and a mixture of LiSn2, LiSn, Li5Sn2 and Li7Sn2 alloys is detected during the insertion. For the TBCO, which is revealed as amorphous, mainly constituted by randomly distributed very short-range (order of 10-9 m) regions by TEM observation, it is found that electrochemically inserted lithium forms Li2O and produces metallic tin (Sn) in the first step (Li/Sn <2), then the highly ionic lithium-tin alloys, Li7Sn2 (and Li7Si2), are produced in the second step (Li/Sn >2). During the second step, the Li/Sn ratio of formed lithium-tin alloy is kept at almost 4. By the analyses of 7Li NMR Knight shifts, line shape and in situ XRD, the lithium-inserted TBCOs are characterized as almost amorphous and mixtures of highly ionic components.

  19. Ion-pairing in aqueous CaCl2 and RbBr solutions: Simultaneous structural refinement of XAFS and XRD data

    NASA Astrophysics Data System (ADS)

    Pham, Van-Thai; Fulton, John L.

    2013-01-01

    We present a new methodology involving the simultaneous refinement of both x-ray absorption and x-ray diffraction spectra (x-ray absorption/diffraction structural refinement, XADSR) to study the hydration and ion pair structure of CaCl2 and RbBr salts in concentrated aqueous solutions. The XADSR method combines the x-ray absorption fine structure (XAFS) spectral analysis of both the cation and anion as a probe of their short-range structure with an x-ray diffraction (XRD) spectral analysis as a probe of the global structural. Together they deliver a comprehensive picture of the cation and anion hydration, the contact ion pair (CIP) structure, and the solvent-separated ion pair (SSIP) structure. XADSR analysis of 6.0 m aqueous CaCl2 reveals that there are ˜0.26 Ca2+-Cl- CIP's separated by about 2.71 Å, while there are 3.4 SSIP's separated by about 4.98 Å. In contrast XADSR analysis of 6 m aqueous RbBr yields about 0.7 pair CIP at a bond length of 3.51 Å. The present work demonstrates a new approach for a direct co-refinement of XRD and XAFS spectra in a simple and reliable fashion, opening new opportunities for analysis in various disordered and crystalline systems.

  20. Mineralogical In-situ Investigation of Acid-Sulfate Samples from the Rio Tinto River, Spain, with a Portable XRD/XRF Instrument

    NASA Technical Reports Server (NTRS)

    Sarrazin, P.; Ming, D. W.; Morris, R. V.; Fernandez-Remolar, D.; Amils, R.; Arvidson, R. E.; Blake, D.; Bish, D. L.

    2007-01-01

    A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved.

  1. Combined In-Situ XRD and In-Situ XANES Studies on the Reduction Behavior of a Rhenium Promoted Cobalt Catalyst

    SciTech Connect

    Kumar, Nitin [Louisiana State University; Payzant, E Andrew [ORNL; Jothimurugesan, K [Chevron Energy Technology Company; Spivey, James J [Louisiana State University

    2011-01-01

    A 10% Co 4% Re/(2% Zr/SiO2) catalyst was prepared by co-impregnation using a silica support modified by 2% Zr. The catalyst was characterized by temperature programmed reduction (TPR), in situ XRD and in situ XANES analysis where it was simultaneously exposed to H2 using a temperature programmed ramp. The results showed the two step reduction of large crystalline Co3O4 with CoO as an intermediate. TPR results showed that the reduction of highly dispersed Co3O4 was facilitated by reduced rhenium by a H2-spillover mechanism. In situ XRD results showed the presence of both, Co-hcp and Co-fcc phases in the reduced catalyst at 400 C. However, the Co-hcp phase was more abundant, which is thought to be the more active phase as compared to the Co-fcc phase for CO hydrogenation. CO hydrogenation at 270 C and 5 bar pressure produces no detectable change in the phases during the time of experiment. In situ XANES results showed a decrease in the metallic cobalt in the presence of H2/CO, which can be attributed due to oxidation of the catalyst by reaction under these conditions.

  2. In situ characterization of uranium and americium oxide solid solution formation for CRMP process: first combination of in situ XRD and XANES measurements.

    PubMed

    Caisso, Marie; Picart, Sébastien; Belin, Renaud C; Lebreton, Florent; Martin, Philippe M; Dardenne, Kathy; Rothe, Jörg; Neuville, Daniel R; Delahaye, Thibaud; Ayral, André

    2015-04-14

    Transmutation of americium in heterogeneous mode through the use of U1-xAmxO2±? ceramic pellets, also known as Americium Bearing Blankets (AmBB), has become a major research axis. Nevertheless, in order to consider future large-scale deployment, the processes involved in AmBB fabrication have to minimize fine particle dissemination, due to the presence of americium, which considerably increases the risk of contamination. New synthesis routes avoiding the use of pulverulent precursors are thus currently under development, such as the Calcined Resin Microsphere Pelletization (CRMP) process. It is based on the use of weak-acid resin (WAR) microspheres as precursors, loaded with actinide cations. After two specific calcinations under controlled atmospheres, resin microspheres are converted into oxide microspheres composed of a monophasic U1-xAmxO2±? phase. Understanding the different mechanisms during thermal conversion, that lead to the release of organic matter and the formation of a solid solution, appear essential. By combining in situ techniques such as XRD and XAS, it has become possible to identify the key temperatures for oxide formation, and the corresponding oxidation states taken by uranium and americium during mineralization. This paper thus presents the first results on the mineralization of (U,Am) loaded resin microspheres into a solid solution, through in situ XAS analysis correlated with HT-XRD. PMID:25742991

  3. Multilayer Magnets

    Microsoft Academic Search

    SL CHEN; W LIU; ZD ZHANG

    2006-01-01

    After experimental evidence of intergrain exchange coupling was reported, nanocomposite magnets with high remanence and large energy products were predicted. However, the experimental values of the maximum magnetic energy product of nanocomposite bulk magnets have been much less than the theoretically predicted ones. We gave a brief review on advances in multilayer magnets. The exchange coupling and remanence enhancement were

  4. Titania deposited on soft magnetic activated carbon as a magnetically separable photocatalyst with enhanced activity

    NASA Astrophysics Data System (ADS)

    Wang, Shaohua; Zhou, Shaoqi

    2010-08-01

    Magnetically separable composite photocatalysts, TiO 2 deposited on soft magnetic ferrite activated carbon (TFAC), were prepared by sol-gel and dip-coating technique. The prepared composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectra (FTIR), optical absorption spectroscopy, vibrating sample magnetometer (VSM) and nitrogen adsorption. These photocatalysts exhibited enhanced photocatalytic activity compared to Degussa P25 for the degradation of methyl orange (MO) in aqueous solution. The kinetics of MO degradation was well fitted to the Langmuir-Hinshelwood model. The samples showed good magnetic response and could be completely recovered by an external magnet. Furthermore, the photocatalysts could maintain high photocatalytic activity after five cycles, and the degradation rate of MO was still close to 90%.

  5. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system. Part 1: Ca-Sr-Cu oxides

    NASA Astrophysics Data System (ADS)

    Reardon, B. J.; Hubbard, C. R.

    1992-01-01

    X-ray powder patterns for the phases in the CaO-SrO-CuO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a simulated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca, Sr)O, (Ca,Sr)2CuO3, (Ca,Sr)14Cu24O41, (Ca,Sr)CuO2, (Ca,Sr)Cu2O3, and (Ca,Sr)Cu2O2 solid solution series and are recommended for the PDF.

  6. Study of the thermal transformations of Co- and Fe-exchanged zeolites A and X by 'in situ' XRD under reducing atmosphere

    SciTech Connect

    Ronchetti, Silvia, E-mail: silvia.ronchetti@polito.it [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)] [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Turcato, Elisa Aurelia; Delmastro, Alessandro [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)] [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Esposito, Serena; Ferone, Claudio; Pansini, Michele [Laboratorio Materiali del Dipartimento di Meccanica, Strutture, Ambiente e Territorio, Facolta di Ingegneria dell'Universita di Cassino, Via G. Di Biasio 43, 03043 Cassino (Italy)] [Laboratorio Materiali del Dipartimento di Meccanica, Strutture, Ambiente e Territorio, Facolta di Ingegneria dell'Universita di Cassino, Via G. Di Biasio 43, 03043 Cassino (Italy); Onida, Barbara; Mazza, Daniele [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)] [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2010-06-15

    'In situ' high temperature X-ray diffraction under reducing atmosphere is used for the first time to study the thermal stability and transformations of Co- and Fe-exchanged A and X zeolites. TG-DTA and 'ex situ' XRD characterization were also carried out. The temperature of incipient crystallization of metallic phase was found to be 700 {sup o}C in Fe-zeolites and 800 {sup o}C in Co-zeolites. Moreover, ex situ X-ray experiments, after thermal treatment both under inert and reducing atmosphere, revealed the formation of ceramic phases upon the thermal collapse of the zeolitic framework. Metal nanoparticles were obtained by reduction and the size of metal clusters was found to range between 24 and 40 nm.

  7. SEM and XRD Characterization of ZnO Nanostructured Thin Films Prepared by Sol-Gel Method with Various Annealing Temperatures

    NASA Astrophysics Data System (ADS)

    Amizam, S.; Abdullah, N.; Rafaie, H. A.; Rusop, M.

    2010-03-01

    ZnO thin films were fabricated by the sol-gel method using Zn(CH3COO)2.2H2O (zinc acetate) as starting material. A homogenous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and ethanolamine. Deposition of ZnO solution on Si substrate was performed by spin-coating technique and annealed at various temperatures from 200° C to 600° C. The surface morphologies and structural properties of the obtained product were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM analysis showed that the surface boundaries of ZnO thin films were decreased with the increasing of annealing temperature. X-ray analysis showed that the crystallinity of ZnO thin films increased with increasing annealing temperature. The effect of annealing temperature of ZnO thin films was studied.

  8. A new approach in quantitative in-situ XRD of cement pastes: Correlation of heat flow curves with early hydration reactions

    SciTech Connect

    Hesse, Christoph; Goetz-Neunhoeffer, Friedlinde; Neubauer, Juergen, E-mail: neubauer@geol.uni-erlangen.d

    2011-01-15

    XRD measurements of the hydration of synthetical cement (SyCem) were used to calculate the resulting heat flow from changes in the phase content. Calculations were performed by application of thermodynamic data. The comparison with data recorded from heat flow calorimetry was in good agreement with the calculated heat flow. The initial maximum of heat flow mainly is caused by the aluminate reaction. During the entire main period the silicate reaction dominates hydration with a high and long first maximum of heat flow. The second but less intense heat flow maximum - only visible as a shoulder in most of the technical cements - can be attributed to an acceleration of the aluminate reaction with the enhanced dissolution of C{sub 3}A and the final formation of ettringite. Moreover, the investigation showed that the dissolution process of C{sub 3}A is directly controlled by the availability of the calcium sulfate phases.

  9. A comprehensive review of the XRD data of the primary and secondary phases present in the BSCCO superconductor system: Part 1, Ca-Sr-Cu oxides

    SciTech Connect

    Reardon, B.J. [Alfred Univ., NY (United States); Hubbard, C.R. [Oak Ridge National Lab., TN (United States)

    1992-01-01

    X-ray powder patterns for the phases in the CaO-SrO-CuO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File (PDF). Available X-ray diffraction (XRD) patterns were compared with each other and, when possible, with a simulated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca, Sr)O, (Ca,Sr){sub 2}CuO{sub 3}, (Ca,Sr){sub 14}Cu{sub 24}O{sub 41}, (Ca,Sr)CuO{sub 2}, (Ca,Sr)Cu{sub 2}O{sub 3}, and (Ca,Sr)Cu{sub 2}O{sub 2} solid solution series and are recommended for the PDF.

  10. Ceria-based Catalysts for the Production of H2 Through the Water-gas-shift Reaction: Time-Resolved XRD and XAFS Studies

    SciTech Connect

    Wang,X.; Rodriguez, J.; Hanson, J.; Gamarra, D.; Marinez-Arias, A.; Fernandez-Garcia, M.

    2008-01-01

    Hydrogen is a potential alternate energy source for satisfying many of our energy needs. In this work, we studied H2 production from the water-gas-shift (WGS) reaction over Ce1-x Cu x O2 catalysts, prepared with a novel microemulsion method, using two synchrotron-based techniques: time-resolved X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). The results are compared with those reported for conventional CuO x /CeO2 and AuO x /CeO2 catalysts obtained through impregnation of ceria. For the fresh Ce1-x Cu x O2 catalysts, the results of XAFS measurements at the Cu K-edge indicate that Cu is in an oxidation state higher than in CuO. Nevertheless, under WGS reaction conditions the Ce1-x Cu x O2 catalysts undergo reduction and the active phase contains very small particles of metallic Cu and CeO2-x . Time-resolved XRD and XAFS results also indicate that Cud+ and Aud+ species present in fresh CuO x /CeO2 and AuO x /CeO2 catalysts do not survive above 200 C under the WGS conditions. In all these systems, the ceria lattice displayed a significant increase after exposure to CO and a decrease in H2O, indicating that CO reduced ceria while H2O oxidized it. Our data suggest that H2O dissociation occurred on the Ovacancy sites or the Cu-Ovacancy and Au-Ovacancy interfaces. The rate of H2 generation by a Ce0.95Cu0.05O2 catalyst was comparable to that of a 5 wt% CuO x /CeO2 catalyst and much bigger than those of pure ceria or CuO.

  11. Ion-pairing in aqueous CaCl2 and RbBr solutions: simultaneous structural refinement of XAFS and XRD data

    SciTech Connect

    Pham, Thai V.; Fulton, John L.

    2013-01-28

    We present a new methodology involving the simultaneous refinement of both x-ray absorption and x-ray diffraction spectra (X-ray Absorption/Diffraction Structural Refinement,XADSR), to study hydration and ion pair structure of CaCl2 and RbBr salts in concentrated aqueous solutions. The XADSR analysis includes the XAFS spectra analysis of both the cation and anion as a probe of their short-range structure with an XRD spectral analysis as a probe of the global structural. Together they deliver a comprehensive picture of the cation and anion hydration, the contact ion pair (CIP) structure and the solvent-separated ion pair (SSIP) structure. XADSR analysis of 6.0 m aqueous CaCl2 reveals that there are an insignificant number of Ca2+-Cl- CIP’s, but there are approximately 3.4 SSIP’s separated by about 4.99 Å. In contrast XADSR analysis of aqueous RbBr yields about 0.7 pair CIP at a bond length 3.51 Å. The present work demonstrates a new approach for a direct co-refinement of XRD and XAFS spectra in a simple and reliable fashion, opening new opportunities for analysis in various disordered and crystalline systems. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the U.S. Department of Energy by Battelle.

  12. [X-ray diffraction (XRD) and near infrared spectrum (NIR) analysis of the soil overlying the Bairendaba deposit of the Inner Mongolia Grassland].

    PubMed

    Luo, Song-ying; Cao, Jian-jin; Wu, Zheng-quan

    2014-08-01

    The soil samples uniformly overlying the Bairendaba deposit of the Inner Mongolia grassland were collected, and ana- lyzed with X-ray diffraction (XRD) and near infrared spectrum (NIR), for exploring the origins of the soil from the, grassland mining area and the relationship with the underground rock. The results show that the samp]s consist of quartz, graphite, carbonate, hornblende, mica, chlorite, montmorillonite, illite, berlinite, diaspore, azurite, hen tite, etc. These indicate that the soil samples were not only from the weathering products of the surface rock, but also from the underground rock mass and the alteration of the wall rock. The azurite and the hematite contained in the soil, mainly coming from the oxidation zone of the orebodies, can be used as the prospecting marks. The alteration mineral assemblage is mainly chlorite-illite-montmorillonite and it experienced the alteration process of potassic alteration-->silicification-->carbonatization-->silk greisenization-->clayization. Also, the wall rock alteration and the physical weathering processes can be accurately restored by analyzing the combination of the alteration minerals, which can provide important reference information for the deep ore prospecting and the ore deposit genesis study, improving the rate of the prospecting. The XRD and NIR with the characteristics of the economy and quickness can be used for the identification of mineral composition of soil, and in the study of mineral and mineral deposits. Especially, NIR has its unique superiority, that is, its sample request is low, and it can analyze a batch of samples quickly. With the development of INR, it will be more and more widely applied in geological field, and can play an important role in the ore exploration. PMID:25508754

  13. [X-ray diffraction (XRD) and near infrared spectrum (NIR) analysis of the soil overlying the Bairendaba deposit of the Inner Mongolia Grassland].

    PubMed

    Luo, Song-ying; Cao, Jian-jin; Wu, Zheng-quan

    2014-08-01

    The soil samples uniformly overlying the Bairendaba deposit of the Inner Mongolia grassland were collected, and ana- lyzed with X-ray diffraction (XRD) and near infrared spectrum (NIR), for exploring the origins of the soil from the, grassland mining area and the relationship with the underground rock. The results show that the samp]s consist of quartz, graphite, carbonate, hornblende, mica, chlorite, montmorillonite, illite, berlinite, diaspore, azurite, hen tite, etc. These indicate that the soil samples were not only from the weathering products of the surface rock, but also from the underground rock mass and the alteration of the wall rock. The azurite and the hematite contained in the soil, mainly coming from the oxidation zone of the orebodies, can be used as the prospecting marks. The alteration mineral assemblage is mainly chlorite-illite-montmorillonite and it experienced the alteration process of potassic alteration-->silicification-->carbonatization-->silk greisenization-->clayization. Also, the wall rock alteration and the physical weathering processes can be accurately restored by analyzing the combination of the alteration minerals, which can provide important reference information for the deep ore prospecting and the ore deposit genesis study, improving the rate of the prospecting. The XRD and NIR with the characteristics of the economy and quickness can be used for the identification of mineral composition of soil, and in the study of mineral and mineral deposits. Especially, NIR has its unique superiority, that is, its sample request is low, and it can analyze a batch of samples quickly. With the development of INR, it will be more and more widely applied in geological field, and can play an important role in the ore exploration. PMID:25474975

  14. TiN Fe nanocomposite thin films deposited by reactive magnetron sputtering

    Microsoft Academic Search

    S. Zerkout; S. Achour; N. Tabet

    2007-01-01

    TiN-Fe films with various iron concentrations were deposited on Si and NaCl single-crystal substrates by direct current reactive magnetron sputtering. The structure and chemical composition of the films were examined by x-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray and x-ray photoelectron spectroscopy (XPS). The effects of Fe addition on the structural, mechanical and magnetic properties of

  15. Facile synthesis of nanocrystalline zinc ferrite via a self-propagating combustion method

    Microsoft Academic Search

    Hun Xue; Zhaohui Li; Xuxu Wang; Xianzhi Fu

    2007-01-01

    Macroporous nanocrystalline zinc ferrite with single spinel-phase was prepared by a facile self-propagating combustion method using zinc nitrate, iron nitrate and glycine. The as-prepared ZnFe2O4 were characterized by X-ray diffraction (XRD) analysis, N2 adsorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectrum (EDS). The magnetic properties of the prepared

  16. Magnetically guided release of ciprofloxacin from superparamagnetic polymer nanocomposites.

    PubMed

    Gupta, Rashmi; Bajpai, A K

    2011-01-01

    Tailored with superparamagnetic properties the magnetic nanocomposites have been thoroughly investigated in recent past because of their potential applications in the fields of biomedicine and bioengineering such as protein detection, magnetic targeted drug carriers, bioseparation, magnetic resonance imaging contrast agents and hyperthermia. Magnetic drug targeting has come up as a safe and effective drug-delivery technology, i.e., with the least amount of magnetic particles a maximum of drug may be easily administered and transported to the site of choice. In the present work novel magnetic drug-targeting carriers consisting of magnetic nanoparticles encapsulated within a smart polymer matrix with potential of controlled drug release is described. To make such magnetic polymeric drug-delivery systems, both the magnetic nanoparticles and antibiotic drug (ciprofloxacin) were incorporated into the hydrogel. The controlled release process and release profiles were investigated as a function of experimental protocols such as percent loading of drug, chemical composition of the nanocomposite, pH of release media and strength of magnetic field on the release profiles. The structure, morphology and compositions of magnetic hydrogel nanocomposites were characterized by FT-IR, TEM, XRD and VSM techniques. It was found that magnetic nanocomposites were biocompatible and superparamagnetic in nature and could be used as a smart drug carrier for controlled and targeted drug delivery. PMID:20566063

  17. Magnetic materials based on iron dispersed in graphitic matrices II. High temperatures and mesophase pitch

    Microsoft Academic Search

    Alexander J. Dyakonov; B. Jack McCormick; Pawan K. Kahol; Hussein H. Hamdeh

    1997-01-01

    Ferromagnetic materials based on iron incorporated into pitch were synthesized, and characterized by magnetic methods (Faraday), Mössbauer spectroscopy, SEM, and XRD. A graphitic-type structure was observed to form at 350–1650°C. The important role of a mesophase structure of a pitch-precursor in the iron carbonyl absorption and anisotropic structure of the resulting iron containing material was found.

  18. Magnetic materials based on iron dispersed in graphitic matrices II. High temperatures and mesophase pitch

    Microsoft Academic Search

    B. J. McCormick; A. J. Dyakonov; P. K. Kahol; H. H. Hamdeh

    1997-01-01

    Ferromagnetic materials based on iron incorporated into pitch were synthesized, and characterized by magnetic methods (Faraday), Mössbauer spectroscopy, SEM, and XRD. A graphitic-type structure was observed to form at 350-1650°C. The important role of a mesophase structure of a pitch-precursor in the iron carbonyl absorption and anisotropic structure of the resulting iron containing material was found.

  19. Fabrication, characterization, and magnetic behavior of porous ZnFe2O4 hollow microspheres

    NASA Astrophysics Data System (ADS)

    Matli, Penchal Reddy; Zhou, Xiaobing; Shiyu, Du; Huang, Qing

    2015-12-01

    Porous ZnFe2O4 hollow microspheres with a diameter of about 100-210 nm were successfully prepared by simple template-free hydrothermal route in ethylene glycol (EG) solution. The formation mechanism and properties have been also demonstrated. The structural, morphological, and magnetic properties of ZnFe2O4 hollow microspheres were investigated by means of X-ray powder diffraction (XRD), field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and physical properties measurements system. The surface area was determined using the BET method. XRD and IR analyses confirm the cubic spinel phase of ZnFe2O4 hollow microspheres. Every magnetic microsphere is made up of many ultrafine ZnFe2O4 nanoparticles with porous structure. The as-prepared porous magnetic hollow spheres have higher surface area and excellent magnetic properties at room temperature.

  20. Development of magnetic composite photocatalytic particles for environmental applications

    NASA Astrophysics Data System (ADS)

    Lee, Seungwoo

    Hard magnetic composite photocatalytic particles were developed for the purpose of enhancing the separation efficiency, reusability, and photocatalytic activity by applying an external magnetic field. Two types of core-shell structured magnetic composite photocatalysts were developed; the first one is composed of barium ferrite (magnetic core)/titania (photoactive shell) and the second one consists of barium ferrite (magnetic core)/silica (intermediate layer)/titania (photoactive shell). The physical and chemical properties of the developed composite particles were characterized using the various analytical instruments (i.e., SEM, TEM, XRD, W-Vis, BET, and EDS) and the photocatalytic activities of the particles were evaluated by the photodegradation of an organic dye under UV irradiation. A magnetically agitated photocatalytic reactor was developed for the hard magnetic composite photocatalyst developed. A simple model was used to estimate the resonant frequency as a function of particle magnetization and magnetic field gradient. The photocatalytic activity of the prepared composite photocatalytic particles in the magnetically agitated photocatalytic reactor was compared to that in the photocatalytic reactor. Various TiO2-SnO2 composite nanoparticles were synthesized with the three different preparation procedures based on the wet-chemical method to improve the overall photocatalytic activity. The crystal structures of the prepared TiO2-SnO2 composite particles were evaluated using XRD and the photocatalytic activities of the composite particles were compared to those of pure TiO2 particles. Furthermore, the developed TiO2-SnO2 composite particles were adopted and tested on the magnetic composite photocatalytic particles.

  1. Conductivity and Magnetic Susceptibility of Nanotube\\/Polypyrrole Nanocomposites

    Microsoft Academic Search

    B. H. Chang; Z. Q. Liu; L. F. Sun; D. S. Tang; W. Y. Zhou; G. Wang; L. X. Qian; S. S. Xie; J. H. Fen; M. X. Wan

    2000-01-01

    A method has been developed to produce a carbon nanotube\\/conducting polymer nano-composite through in-situ polymerization of pyrrole in the carbon nanotube template. The nano-composites of carbon nanotube and polypyrrole have been characterized by SEM, TEM, XRD, Raman Scattering. The thermal stability was studied by TGA (Thermal Gravity Analysis). The measurements of conductivity and magnetic susceptibility of the composites have been

  2. Conductivity and magnetic susceptibility of nanotube/polypyrrole nanocomposites

    SciTech Connect

    Chang, B.H.; Liu, Z.Q.; Sun, L.F. [and others] [and others

    2000-04-01

    A method has been developed to produce a carbon nanotube/conducting polymer nano-composite through in-situ polymerization of pyrrole in the carbon nanotube template. The nano-composites of carbon nanotube and polypyrrole have been characterized by SEM, TEM, XRD, Raman Scattering. The thermal stability was studied by TGA (Thermal Gravity Analysis). The measurements of conductivity and magnetic susceptibility of the composites have been studied.

  3. Magnetic Fields

    NSDL National Science Digital Library

    2014-09-18

    Students visualize the magnetic field of a strong permanent magnet using a compass. The lesson begins with an analogy to the effect of the Earth's magnetic field on a compass. Students see the connection that the compass simply responds to the Earth's magnetic field since it is the closest, strongest field, and thus the compass responds to the field of the permanent magnets, allowing them the ability to map the field of that magnet in the activity. This information will be important in designing a solution to the grand challenge in activity 4 of the unit.

  4. Studies on the magnetism of cobalt ferrite nanocrystals synthesized by hydrothermal method

    Microsoft Academic Search

    Lijun Zhao; Hongjie Zhang; Yan Xing; Shuyan Song; Shiyong Yu; Weidong Shi; Xianmin Guo; Jianhui Yang; Yongqian Lei; Feng Cao

    2008-01-01

    Fe–Co\\/CoFe2O4 nanocomposite and CoFe2O4 nanopowders were prepared by the hydrothermal method. The structure of magnetic powders were characterized by X-ray diffraction diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermal gravity analysis (TGA) and differential thermal analysis (DTA) analysis, X-ray photoelectron spectrometry (XPS), and Fourier transform infrared spectra (FTIR) techniques, while magnetic properties were determined by

  5. Study of room temperature ferromagnetism for cobalt and manganese doped ZnO diluted magnetic semiconductor

    Microsoft Academic Search

    R. K. Singhal; Arvind Samariya; Y. T. Xing; S. N. Dolia; Sudhish Kumar; U. P. Deshpande; T. Shripathi; Elisa Saitovitch

    2010-01-01

    We report the results of electronic and magnetic properties of poly-crystalline Zn1-xMxO (M = Co and Mn) pellets studied by XRD, VSM and XPS. The specimens were synthesized by solid state reaction method using high purity oxides. Samples exhibit Wurtzite hexagonal symmetry and show interesting magnetic properties. The Co (5%) doped sample prepared by heating in air shows a paramagnetic

  6. Intrinsic ferromagnetic properties in Cr-doped ZnO diluted magnetic semiconductors

    Microsoft Academic Search

    Yang Liu; Yanting Yang; Jinghai Yang; Qingfeng Guan; Huilian Liu; Lili Yang; Yongjun Zhang; Yaxin Wang; Maobin Wei; Xiaoyan Liu; Lianhua Fei; Xin Cheng

    2011-01-01

    The Cr-doped zinc oxide (Zn1?xCrxO, 0?x?0.08) diluted magnetic semiconductors have been synthesized successfully by the sol–gel method. Investigations on magnetic, optical and structural properties of the produced samples have been done. Energy dispersive spectroscopy (EDS) shows the existence of Cr ion in the Cr-doped ZnO. The results of X-ray diffraction (XRD), the transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS)

  7. Novelty, preparation, characterization and enhancement of magnetic properties of Mn nanoferrites using safety binder (egg white)

    Microsoft Academic Search

    M. A. Ahmed; N. Okasha; S. I. El-Dek

    2011-01-01

    Nanocrystalline MnFe2O4 ferrite was prepared by using autocombustion technique (flash). The microstructure and magnetic properties are studied. The results of XRD and TEM clarified that, this ferrite is nanosized with particle size (39 nm). Magnetic measurements showed a ferromagnetic behavior with TC = 613 K, the saturation magnetization Ms = 13.71 emu\\/g, remanent magnetization Mr = 0.1694 emu\\/g and, coercivity Hc = 25.6 Oe. Natural material, egg white used as an aqueous medium

  8. Directional role of weak magnetic field on the self-fabrication of ordered nickel chains

    NASA Astrophysics Data System (ADS)

    Li, Xueliang; Han, Changlong

    2007-11-01

    Novel ordered nickel chains with diameter 250-500 nm and length more than 5 ?m were synthesized under weak magnetic field by hydrazine reducing in ethylene glycol. The phase, morphology and magnetic properties were characterized by X-ray diffraction (XRD), scanning electron microanalyzer (SEM) and vibrating sample magnetometer (VSM), respectively. The results reveal that weak magnetic field leads to the fabrication of nickel chains paralleling each other with hierarchical structures. The growth mechanism and fabrication process of nickel magnetic nanocrystallites were discussed.

  9. Preparation of magnetic composite microspheres by surfactant free controlled radical polymerization: Preparation and characteristics

    NASA Astrophysics Data System (ADS)

    Zhang, Hepeng; Zhang, Qiuyu; Zhang, Baoliang; Guo, Feige

    2009-12-01

    Submicron magnetic composite microspheres have been prepared by a new surfactant free controlled radical polymerization. This new approach is based on the use of diphenylethene (DPE) as radical controlling agent and no emulsifier is required. X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM), etc. were conducted to characterize the magnetite particles and magnetic composite microspheres. The average size of the magnetic composite microspheres prepared by this new approach is 265 nm and the magnetite content of the composite microspheres is around 20%. Furthermore, the magnetic composite microspheres which surfaces have epoxy groups were also prepared.

  10. X-radiography, XRD and Ultrasonic Data Transfer Function Technique - Simultaneous Measurements Under Simulated Mantle Conditions in a Multi-Anvil Device

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.; Schilling, F. R.; Lathe, C.

    2004-05-01

    The interpretation of seismic data from the Earth's deep interior requires measurements of the physical properties of Earth materials under experimental simulated mantle conditions. Elastic wave velocity measurement is an important tool for the determination of the elastic properties. Ultrasonic interferometry allows the highly precise travel time measurement at a sample enclosed in a high-pressure multi-anvil device. But the calculation of wave velocities requires the exact sample length under in situ conditions. There are two options - scanning the interfaces of the sample by XRD (Mueller et al., 2003) and X-radiography (Li et al., 2001). The multi-anvil apparatus MAX80 is equipped for both methods. Only the X-radiography is fast enough for transient measurements. Contrary to XRD measurements, imaging the sample by X-rays requires a beam diameter larger than the sample length. Therefore the fixed primary slits of Max80 were exchanged by 4-blade high precision slits of Advanced Design Consulting, Inc. A Ce-YAG-crystal converts the X-ray image to an optical one, redirected by a mirror and captured by a CCD-camera. To derive the sample length, the different brightness of sample, buffer rod and reflector at the electronic image is evaluated. Classical ultrasonic interferometry is very time consuming, because the ultrasonic waves of the frequency range under study are generated and detected one after another with a given step rate. A 60 MHz frequency sweep with 100 kHz steps lasts for more than 30 minutes. This is a serious limitation for all transient measurements, but also limits the data collection at elevated temperatures to prevent the pressure transmitting boron epoxy cubes and the anvils from overheating. The ultrasonic transfer function technique (UTF), first described by Li et al. (2002), generates all the frequencies simultaneously. Related to the results and experiences of Li the UTF-technique was developed independently at GFZ. This version allows to consider the characteristics of the specific transducer-glue-anvil combination (Mueller et al., 2003). To collect the data for the following calculation of Vp and Vs requires just few seconds. The excitation function, applied to the transducer by an arbitrary waveform generator, is the result of the summation of all sinusoidal waves inside the frequency range. The response of the system - transducer - anvil - buffer rod - sample - reflector - for each of the frequencies can be reproduced by convoluting the resulting transfer function with these monochromatic waves step by step. Some recent results on the non-quenchable high-P - low-P clinoenstatite transition and to the quartz-coesite transition will be given to discuss the different interferometric techniques, including the XRD-data and X-radiography results, necessary to detect the phase transitions under in situ conditions and to measure the sample deformation. Li, B.; Vaughan, M.T.; Kung, J.; Weidner, D.J., NSLS Activity Report 2001, 2-103-106, (2001). Li, B.; Chen, K.; Kung, J.; Liebermann, R.C.; Weidner, D.J., J. Phys.: Condens. Matter 14, 11337-11342, (2002). Mueller, H.J.; Schilling, F.R.; Lauterjung, J.; Lathe, C., Eur. J. Mineral., 15, 865-873, (2003). Mueller, H.J.; Wunder, B.; Lathe, C.; Schilling, F.R.; Eur. J. Mineral., submitted, (2004).

  11. Synthesis, characterization and magnetic properties of carbon nanotubes decorated with magnetic MIIFe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ali, Syed Danish; Hussain, Syed Tajammul; Gilani, Syeda Rubina

    2013-04-01

    In this study, a simple, efficient and reproducible microemulsion method was applied for the successful decoration of carbon nanotubes (CNTs) with magnetic MIIFe2O4 (M = Co, Ni, Cu, Zn) nanoparticles. The structure, composition and morphology of the prepared nanocomposite materials were characterized using X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The magnetic properties were investigated by the vibrating sample magnetometer (VSM). The SEM results illustrated that large quantity of MIIFe2O4 nanoparticles were uniformly decorated around the circumference of CNTs and the sizes of the nanoparticles ranged from 15 to 20 nm. Magnetic hysteresis loop measurements revealed that all the MIIFe2O4/CNTs nanocomposites displayed ferromagnetic behavior at 300 K and can be manipulated using an external magnetic field. The CoFe2O4/CNTs nanocomposite showed maximum value of saturation magnetization which was 37.47 emu g-1. The as prepared MIIFe2O4/CNTs nanocomposites have many potential application in magnetically guided targeted drug delivery, clinical diagnosis, electrochemical biosensing, magnetic data storage and magnetic resonance imaging.

  12. Magnetic Declination

    NSDL National Science Digital Library

    National Geophysical Data Center

    A page with basic information about magnetic declination and how it changes over time. The page includes a calculator to determine the magnetic declination at your location, as well as tools for comparing the current declination to historical declination.

  13. Magnetic Fields

    E-print Network

    Schöller, Markus

    2015-01-01

    In this chapter, we give a brief introduction into the use of the Zeeman effect in astronomy and the general detection of magnetic fields in stars, concentrating on the use of FORS2 for longitudinal magnetic field measurements.

  14. Planetary magnetism

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1981-01-01

    A synoptic view of early and recent data on the planetary magnetism of Mercury, Venus, the moon, Mars, Jupiter, and Saturn is presented. The data on Mercury from Mariner 10 are synthesized with various other sources, while data for Venus obtained from 120 orbits of Pioneer Venus give the upper limit of the magnetic dipole. Explorer 35 Lunar Orbiter data provided the first evidence of lunar magnetization, but it was the Apollo subsatellite data that measured accurately the magnetic dipole of the moon. A complete magnetic survey of Mars is still needed, and only some preliminary data are given on the magnetic dipole of the planet. Figures on the magnetic dipoles of Jupiter and Saturn are also suggested. It is concluded that if the magnetic field data are to be used to infer the interior properties of the planets, good measures of the multiple harmonics in the field are needed, which may be obtained only through low altitude polar orbits.

  15. Induced magnetic anisotropy in Si-free nanocrystalline soft magnetic materials: A transmission x-ray diffraction study

    NASA Astrophysics Data System (ADS)

    Parsons, R.; Yanai, T.; Kishimoto, H.; Kato, A.; Ohnuma, M.; Suzuki, K.

    2015-05-01

    In order to better understand the origin of field-induced anisotropy (Ku) in Si-free nanocrystalline soft magnetic alloys, the lattice spacing of the bcc-Fe phase in nanocrystalline Fe94-xNb6Bx (x = 10, 12, 14) alloys annealed under an applied magnetic field has been investigated by X-ray diffraction in transmission geometry (t-XRD) with the diffraction vector parallel and perpendicular to the field direction. The saturation magnetostriction (?s) of nanocrystalline Fe94-xNb6Bx was found to increase linearly with the volume fraction of the residual amorphous phase and is well described by taking into account the volume-weighted average of two local ?s values for the bcc-Fe nanocrystallites (-5 ± 2 ppm) and the residual amorphous matrix (+8 ± 2 ppm). The lattice distortion required to produce the measured Ku values (˜100 J/m3) was estimated via the inverse magnetostrictive effect using the measured ?s values and was compared to the lattice spacing estimations made by t-XRD. The lattice strain required to produce Ku under the magnetoelastic model was not observed by the t-XRD experiments and so the findings of this study suggest that the origin of magnetic field induced Ku cannot be explained through the magnetoelastic effect.

  16. Following the movement of Cu ions in a SSZ-13 zeolite during dehydration, reduction and adsorption: a combined in situ TP-XRD, XANES/DRIFTS study

    SciTech Connect

    Kwak, Ja Hun; Varga, Tamas; Peden, Charles HF; Gao, Feng; Hanson, Jonathan C.; Szanyi, Janos

    2014-05-05

    Cu-SSZ-13 has been shown to possess high activity and superior N2 formation selectivity in the selective catalytic reduction of NOx under oxygen rich conditions. Here, a combination of synchrotron-based (XRD and XANES) and vibrational (DRIFTS) spectroscopy tools have been used to follow the changes in the location and coordination environment of copper ions in a Cu-SSZ-13 zeolite during calcinations, reduction with CO, and adsorption of CO and H2O. XANES spectra collected during these procedures provides critical information not only on the variation in the oxidation state of the copper species in the zeolite structure, but also on the changes in the coordination environment around these ions as they interact with the framework, and with different adsorbates (H2O and CO). Time-resolved XRD data indicate the movement of copper ions and the consequent variation of the unit cell parameters during dehydration. DRIFT spectra provide information about the adsorbed species present in the zeolite, as well as the oxidation states of and coordination environment around the copper ions. A careful analysis of the asymmetric T-O-T vibrations of the CHA framework perturbed by copper ions in different coordination environments proved to be especially informative. The results of this study will aid the identification of the location, coordination and oxidation states of copper ions obtained during in operando catalytic studies. Financial support was provided by the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. Part of this work (sample preparation) was performed in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The EMSL is a national scientific user facility supported by the US DOE, Office of Biological and Environmental Research. PNNL is a multi-program national laboratory operated for the US DOE by Battelle. All of the spectroscopy work reported here was carried out at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL). NSLS is a national scientific user facility supported by the US DOE.

  17. Structural changes and thermal stability of charged LiNixMnyCozO? cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy

    DOE PAGESBeta

    Bak, Seong-Min [Brookhaven National Lab. (BNL), Upton, NY (United States); Hu, Enyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhou, Yongning [Brookhaven National Lab. (BNL), Upton, NY (United States); Yu, Xiqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cho, Sung-Jin [Johnson Control Advanced Power Solution, Milwaukee, WI (United States); North Carolina A&T State Univ., Greensboro, NC (United States); Kim, Kwang-Bum [Yonsei Univ., Seoul (Republic of Korea); Chung, Kyung Yoon [Korea Inst. of Science and Technology, Seoul (Republic of Korea); Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States); Nam, Kyung-Wan [Dongguk Univ., Seoul (Republic of Korea)

    2014-12-24

    Thermal stability of charged LiNixMnyCozO? (NMC with x+y+z=1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time resolved X-ray diffraction and mass spectroscopy (TR- XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability comparable to the low Ni-content materials (e.g., NMC333 and NMC433) while having a high capacity close to the high Ni-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of layered structure (R3m ) but Co ions prefer to migrate to the 8a tetrahedral sites of spinel structure (Fd3m ) during the thermal decomposition. Such elemental dependent cation migration plays a very important role for the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of Ni- to Mn- and Co- contents. This systematic study provides insight into the rational design of NMC based cathode materials with a desired balance between thermal stability and high energy density

  18. Magnetic Pendulums

    NSDL National Science Digital Library

    The Exploratorium

    2011-12-05

    In this activity and demonstration about electricity and magnetism, learners observe how the current generated when one copper coil swings through a magnetic field starts a second coil swinging. Learners also explore what happens when they change the polarity of the magnet, reverse the coil, or add a clip lead to short-circuit the coils. Use this activity to illustrate how electricity and magnetism interact. The assembly of the electromagnetic swing device takes about an hour.

  19. Magnetism Hunt

    NSDL National Science Digital Library

    2012-06-26

    In this activity about magnetism (page 4 of the PDF), learners will experiment with magnets and different objects to find out that not all metals are attracted to magnets. Even though there are only a few supplies listed, the possibilities are really endless when it comes to what learners can try to attract to the magnet. Learners make predictions and compare their predictions to actual outcomes.

  20. Magnetic Storms

    NSDL National Science Digital Library

    2012-08-03

    This is a lesson to introduce the Kp index, a common numerical indicator of magnetic storminess. Learners will access and analyze Kp index plots of magnetic storm strength and determine the relative frequency of stronger versus weaker magnetic storms during years of maximum solar activity. This resource is activity 13 from the Magnetic Mysteries of the Aurora teachers guide. Internet access is required for this activity.

  1. Superconducting magnets

    SciTech Connect

    Willen, E.

    1996-12-31

    Superconducting dipole magnets for high energy colliders are discussed. As an example, the magnets recently built for the Relativistic Heavy Ion Collider at Brookhaven are reviewed. Their technical performance and the cost for the industry-built production dipoles are given. The cost data is generalized in order to extrapolate the cost of magnets for a new machine.

  2. Superconducting magnets

    SciTech Connect

    Not Available

    1994-08-01

    This report discusses the following topics on superconducting magnets: D19B and -C: The next steps for a record-setting magnet; D20: The push beyond 10 T: Beyond D20: Speculations on the 16-T regime; other advanced magnets for accelerators; spinoff applications; APC materials development; cable and cabling-machine development; and high-{Tc} superconductor at low temperature.

  3. Magnetic Suction

    NSDL National Science Digital Library

    The Exploratorium

    2012-11-13

    In this activity about electricity and magnetism, learners discover how a doorbell works. A coil of wire with current flowing through it forms an electromagnet that acts similar to a bar magnet. The coil will magnetize an iron nail and attract it in a remarkably vigorous way.

  4. Seeing Magnetism

    NSDL National Science Digital Library

    This is lesson to begin learners' thinking about magnetic influence. Learners will watch a classroom demonstration about the effect of magnets on iron filings and then complete a journal assignment to record their reactions and thoughts. This is the first activity in the Mapping Magnetic Influence educators guide.

  5. Optical and magnetic properties of zinc oxide quantum dots doped with cobalt and lanthanum.

    PubMed

    Yu, Shiyong; Zhao, Jing; Su, Hai-Quan

    2013-06-01

    Cobalt and Lanthanum-doped ZnO QDs are synthesized by a modified sol-gel method under atmospheric conditions. The as-prepared quantum dots are characterized by X-ray powder diffraction (XRD), energy dispersive X-ray (EDX) analysis and high resolution transmission electron microscopy (HRTEM). The optical properties of the products are studied by fluorescent spectroscopy. With a proper Co and La doping, these nanoparticles possess exceptionally small size and enhanced fluorescence. Hysteresis loops of un-doped ZnO QDs and Co and La-doped ZnO QDs indicate that both the samples show ferromagnetic behavior at room temperature. Finally, these nanoparticles can label the BGC 803 cells successfully in short time and present no evidence of toxicity or adverse affect on cell growth even at the concentration up to 1 mM. We expect that the as-prepared Co and La-doped ZnO QDs can provide a better reliability of the collected data and find promising applications in biological, medical and other fields. PMID:23862449

  6. Magnetic Field Safety Magnetic Field Safety

    E-print Network

    McQuade, D. Tyler

    Magnetic Field Safety Training #12;Magnetic Field Safety Strong Magnetic Fields exist around energized magnets. High magnetic fields alone are a recognized hazard only for personnel with certain fields will rapidly accelerate any magnetic material towards the magnet. § Magnetic material is commonly

  7. Experimental (XRD, FT-IR and UV-Vis) and theoretical modeling studies of Schiff base (E)-N?-((5-nitrothiophen-2-yl)methylene)-2-phenoxyaniline

    NASA Astrophysics Data System (ADS)

    Tanak, Hasan; A?ar, Ay?en Alaman; Büyükgüngör, Orhan

    2014-01-01

    The Schiff base compound (E)-N?-((5-nitrothiophen-2-yl)methylene)-2-phenoxyaniline has been synthesized and characterized by IR, UV-Vis, and X-ray diffraction (XRD) methods. The molecular geometry from X-ray experiment in the ground state has been compared using the density functional theory (DFT) with the 6-311++G(d,p) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure, and the theoretical vibrational frequency values show good agreement with experimental values. By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. The energetic behavior of the title compound in solvent media has been examined using B3LYP method with the 6-311++G(d,p) basis set by applying the Onsager and the integral equation formalism polarizable continuum model (IEF-PCM). The predicted nonlinear optical properties of the title compound are greater than ones of urea. In addition, DFT calculations of the title compound, molecular electrostatic potential (MEP), natural bond orbital (NBO) and thermodynamic properties were performed at B3LYP/6-311++G(d,p) level of theory.

  8. In situ XRD analysis of the oxide layers formed by oxidation at 743 K on Zircaloy 4 and Zr-1NbO

    NASA Astrophysics Data System (ADS)

    Pétigny, N.; Barberis, P.; Lemaignan, C.; Valot, Ch.; Lallemant, M.

    2000-08-01

    Two alloys, having different oxidation behaviour (Zy4 and Zr-1NbO), have been investigated during oxidation at high temperature (743 K) and low oxygen pressure (10 kPa) by in situ X-ray diffraction (XRD). Tetragonal phase content and 'pseudo-stresses' on the monoclinic phase have been measured as a function of the oxide layer thickness. The tetragonal phase contents are similar for both alloys and decreased with the oxide layer thickness. Pseudo-stresses were much more compressive on Zr-1NbO alloy, with limited changes at the corrosion kinetics transition. On cooling, the tetragonal fractions do not change, while 'pseudo-stresses' decreased in different ways for the two alloys. With respect to stress analysis, no correlation was found between 'pseudo-stresses' and tetragonal phase content. In addition, due to the thermoelastic properties of the highly anisotropic phases of the zirconia, large internal thermal stresses are expected to develop during any temperature changes. The orders of magnitude of them are similar to the stresses induced by swelling during oxidation from Zr to ZrO 2.

  9. XAFS and XRD Study of the Atomic Displacements in Aurivillius Phase Ferroelectric Bi2.25Ca0.5Na0.25Nb2O9

    SciTech Connect

    Vlasenko, Valery G.; Shuvaev, Anatoliy T.; Pirog, Irina V.; Drannikov, Dmitriy; Zarubin, Ivan A. [Research Institute of Physics, Rostov State University, pr. Stachki 194, Rostov-on-Don, 344090 (Russian Federation)

    2007-02-02

    The novel layered perovskite-like oxide with Aurivillius phase structure Bi2.25Ca0.5Na0.25Nb2O9 has been synthesized by solid-state reaction method. This compound is a ferroelectric with the Curie temperature 972 K. The crystal structure of Bi2.25Ca0.5Na0.25Nb2O9 has been determined from powder diffraction data recorded at room temperature. The parameters of the orthorhombic cell (space group A21am) are: a=5.4845 A, b=5.4549 A, c=24.9195 A. Using the profile of the X-ray diffraction pattern the atomic coordinates have been refined by Rietveld method and the Nb ion position in the oxygen octahedra has been found. It was shown that the Nb ion is displaced from the center of the oxygen octahedra by {approx}0.15 A. Nb K-edge EXAFS spectra were measured over the temperature range 295 K - 960 K. The interatomic distances Nb-O and the mean-square relative displacements {sigma}2 have been determined. The interatomic distances Nb-O at room temperature obtained from XAFS analysis are in a good agreement with those found from XRD data. It was revealed that the temperature increase results in the decreasing of Nb ion displacements from the center of the oxygen octahedra. However, in the vicinity of the ferroelectric phase transition the displacement of Nb ion was preserved.

  10. Molecular structure and spectroscopic analysis of 1,4-Bis(1-methyl-2-benzimidazolyl)benzene; XRD, FT-IR, dispersive-Raman, NMR and DFT studies.

    PubMed

    Eren, Bilge; Unal, Arslan

    2013-02-15

    This study reports the structural characterization of a bis-benzimidazole derivative, 1,4-Bis(1-methyl-2-benzimidazolyl)benzene (BMBB), by using spectroscopic and quantum chemical methods. The BMBB molecule was synthesized under microwave conditions and was characterized by using single-crystal X-ray diffraction, FT-IR, dispersive Raman and NMR spectroscopies. The potential energy surface scan study was carried out for the conformation of the theoretical structure. Quantum chemical calculations of relative energies, molecular geometry, vibrational wavenumbers, frontier molecular orbitals, atomic charges and gauge including atomic orbital (GIAO) (1)H and (13)C-NMR chemical shifts of the compound were carried out by using density functional method (DFT) at B3LYP/6-311++G(d,p) theory level. The complete assignments of the vibrational modes were performed with DFT calculations combined with scaled quantum mechanics force field (SQMFF) methodology. A satisfactory consistency between the experimental and theoretical findings was obtained. On account of the relative energies, population analysis and XRD results, the most stable conformational form of the molecule was also determined. PMID:23261617

  11. Redox Behavior of VI B Transition Metal Ions in Rutile TiO 2 Solid Solutions: An XRD and EPR Study

    NASA Astrophysics Data System (ADS)

    Cordischi, Dante; Gazzoli, Delia; Occhiuzzi, Manlio; Valigi, Mario

    2000-07-01

    CrO2-TiO2 (TC), MoO2-TiO2 (TMo), and WO2-TiO2 (TW), prepared by heating in vacuo at 1173-1273 K mixtures of MO2 (M=Cr, Mo, or W) and TiO2, were characterized by XRD and EPR. The transition metal ions were incorporated as isolated and clustered CrIII, MoIV, and WIV and a small fraction as isolated MoV and WV in substitutional sites. After heating in air or in O2 up to 1273 K, in TC no isolated CrV formed, whereas in TMo and TW, MIV was oxidized to MV and MVI, and MO3 was segregated. The oxidation started at 673 K and gave isolated substitutional MoV and isolated interstitial and substitutional WV. After heating in H2 up to 1073 K, TMo and TW reduction process differed: MoIV gave isolated and clustered MoIII, and MoIV-MoIV pairs gave Mo7+2 species; WIV was not reduced to WIII; and temperatures >900 K caused the segregation of metallic molybdenum and tungsten.

  12. The Mineralogy of Martian Dust: Design and Analysis Considerations for an X-Ray Diffraction/X-Ray Fluorescence (XRD/XRF) Instrument for Exobiological Studies

    NASA Technical Reports Server (NTRS)

    Blake, David; Vaniman, David; Bish, David; Morrison, David (Technical Monitor)

    1994-01-01

    A principal objective of Mars exploration is the search for evidence of past life which may have existed during an earlier clement period of Mars history. We would like to investigate the history of surface water activity (which is a requirement for all known forms of life) by identifying and documenting the distribution of minerals which require water for their formation or distribution. A knowledge of the mineralogy of the present Martian surface would help to identify areas which, due to the early activity of water, might have harbored ancient life. It would be desirable to establish the presence and characterize the distribution of hydrated minerals such as clays, and of minerals which are primarily of sedimentary origin such as carbonates, silica and evaporites. Mineralogy, which is more critical to exobiological exploration than is simple chemical analysis (absent the detection of organics), will remain unknown or will at best be imprecisely constrained unless a technique sensitive to mineral structure such as powder X-ray diffraction (XRD) is employed. Additional information is contained in the original extended abstract.

  13. Measurement methods for surface oxides on SUS 316L in simulated light water reactor coolant environments using synchrotron XRD and XRF

    NASA Astrophysics Data System (ADS)

    Watanabe, Masashi; Yonezawa, Toshio; Shobu, Takahisa; Shoji, Tetsuo

    2013-03-01

    Synchrotron X-ray diffraction (XRD) and X-ray fluorescent (XRF) measurement techniques have been used for non-destructive characterization of surface oxide films on Type 316L austenitic stainless steels that were exposed to simulated primary water environments of pressurized water reactors (PWR) and boiling water reactors (BWR). The layer structures of the surface spinel oxides were revealed ex situ after oxidation by measurements made as a function of depth. The layer structure of spinel oxides formed in simulated PWR primary water should normally be different from that formed in simulated BWR water. After oxidation in the simulated BWR environment, the spinel oxide was observed to contain NiFe2O4 at shallow depths, and FeCr2O4 and Fe3O4 at deeper depths. By contrast, after oxidation in the simulated PWR primary water environment, a Fe3O4 type spinel was observed near the surface and FeCr2O4 type spinel near the interface with the metal substrate. Furthermore, by in situ measurements during oxidation in the simulated BWR environment, it was also demonstrated that the ratio between spinel and hematite Fe2O3 can be changed depending on the water condition such as BWR normal water chemistry or BWR hydrogen water chemistry.

  14. Synthesis, spectral, stereochemical, single crystal XRD and biological studies of 3t-pentyl-2r,6c-diarylpiperidin-4-one picrate derivatives

    NASA Astrophysics Data System (ADS)

    Savithiri, S.; Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.

    2014-10-01

    Various substituted 3t-pentyl-2r,6c-diphenylpiperidin-4-one picrates (1-7) were synthesised and characterised by elemental analysis, FT-IR and NMR spectral studies. NMR spectral assignments were made unambiguously by their one dimensional (1H NMR and 13C NMR) and two dimensional (1H-1H COSY, HSQC, HMBC, NOESY, DEPT) NMR spectra. Single crystal XRD analysis of the compound (1) has confirmed that the complex crystallized in monoclinic system with P21/n space group. The difference in the chemical shifts between equatorial methylene proton and axial proton at C(5) [? = ?eq - ?ax] is highly negative in compounds 1-7 in contrast to the value observed for the corresponding parent piperidine-4-one and is indicative of the 1,3-diaxial interaction between the axial NH bond and axial hydrogen at C(5). The chemical shifts of the heterocyclic ring protons are influenced by the picrate anion. All the synthesised compounds exhibited good activity against S. aureus-Staphylococcus aureus bacterial strains and C. albicans fungal strains.

  15. Ferro- and antiferro-magnetism in (Np, Pu)BC

    NASA Astrophysics Data System (ADS)

    Klimczuk, T.; Shick, A. B.; Kozub, A. L.; Griveau, J.-C.; Colineau, E.; Falmbigl, M.; Wastin, F.; Rogl, P.

    2015-04-01

    Two new transuranium metal boron carbides, NpBC and PuBC, have been synthesized. Rietveld refinements of powder XRD patterns of {Np,Pu}BC confirmed in both cases isotypism with the structure type of UBC. Temperature dependent magnetic susceptibility data reveal antiferromagnetic ordering for PuBC below TN = 44 K, whereas ferromagnetic ordering was found for NpBC below TC = 61 K. Heat capacity measurements prove the bulk character of the observed magnetic transition for both compounds. The total energy electronic band structure calculations support formation of the ferromagnetic ground state for NpBC and the antiferromagnetic ground state for PuBC.

  16. Enhancement of magnetization of Mg–Mn nanoferrite by ?-irradiation

    Microsoft Academic Search

    N. Okasha

    2010-01-01

    Mg–Mn nanoparticles ferrites are prepared by a simple and cost-effective method. The influence of gamma-irradiation on the structural and magnetic properties on MgxMn1?xFe2O4; x=0. 0, 0.15, and 0.25 ferrite nanoparticles have been studied. A facile as-prepared method, nanoparticles formed. The well-characterized nanoparticles by X-ray diffraction (XRD) analyses, transmission electron microscope (TEM), and the magnetic properties studied. The results reveal that,

  17. Effects of coating on magnetic properties in iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Bittova, B.; Poltierova-Vejpravova, J.; Roca, A. G.; Morales, M. P.; Tyrpekl, V.

    2010-01-01

    We have studied influence of surface modification on physical properties of iron oxide nanoparticles. We compared samples prepared by thermal decomposition of organic precursor in the presence of oleic acid, and the particles prepared by coprecipitation and partially coated by SiO2 or modified by citric acid and subsequently covered by photoactive TiO2 layer, respectively. Samples were characterised using TEM and XRD, further magnetic studies such as temperature dependence of magnetization and a.c. susceptibility show superparamagnetic behavior for all samples at room temperature. The effects of coating on dipolar inter particle interactions are discussed.

  18. Magnetic properties of Bi-doped Y 3Fe 5O 12 nanoparticles

    Microsoft Academic Search

    Haitao Xu; Hua Yang; Wei Xu; Lianxiang Yu

    2008-01-01

    Bi3+ substituted garnet nanoparticles Y3?xBixFe5O12 (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 and 1.3) were fabricated by a sol–gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), IR spectroscopy, thermal gravity analysis–differential thermal analysis (TG-DTA), transmission electron microscope (TEM), Mössbauer spectroscopy and vibrating sample magnetometer (VSM). The XRD patterns of Y3?xBixFe5O12 have only

  19. Molecular Magnetism

    NASA Astrophysics Data System (ADS)

    Blundell, Stephen J.

    Most materials in magnetic applications are based on inorganic materials. Recently, however, organic and molecular materials have begun to show increasing promise. Purely organic ferromagnets, based upon nitronyl nitroxide radicals, show long range magnetic order at very low temperatures in the region of 1 K, while sulphur-based radicals show weak ferromagnetism at temperatures of up to 36 K. It is also possible to prepare molecule-based magnets in which transition-metal ions are used to provide the magnetic moment, but organic groups mediate the interactions. This strategy has produced magnetic materials with a large variety of structures, including chains, layered systems, and three-dimensional networks, some of which show ordering at room temperature and some of which have very high coercivity. Even if long range magnetic order is not achieved, interesting materials displaying the spin crossover effect may be prepared and these can have useful applications. Further magnetic materials may be obtained by constructing chargetransfer salts, which can produce metallic molecular magnets. A very exciting recent development is the preparation of single molecule magnets, which are small magnetic clusters. These materials can show macroscopic quantum tunnelling of the magnetization and may have uses as memory devices or in quantum computation applications. These systems can be powerfully studied using various experimental methods, including magnetometry, neutron scattering, muon-spin rotation and synchrotron radiation techniques.

  20. Dispersion of magnetic nanoparticles in polymer films

    NASA Astrophysics Data System (ADS)

    Gass, J.

    2005-03-01

    Magnetic nanoparticles embedded in polymer matrices have excellent potential for EMI shielding and biomedical applications. However, uniform dispersion of particles in polymers without agglomeration is quite challenging. We have fabricated PMMA/polypyrrole bilayer structures embedded with Fe3O4 magnetic nanoparticles (mean size ˜ 12 nm) synthesized using wet chemical methods. The magnetic polymer nanocomposites were spin-coated on various substrates. Agglomeration-free dispersion of nanoparticles was achieved by coating the particles with surfactants and by dissolving both the particles and PMMA in cholorobenzene. Structural characterization was done using XRD and TEM. Magnetic properties of the bilayer structures indicated that the superparamagnetic and ferromagnetic response of the polymer nanocomposites including parameters such as the coercivity, remanence and saturation magnetization could be systematically varied with controlled amounts of nanoparticle dispersions in the polymer media. The RF impedance up to frequencies of 3 GHz measured using a vector network analyzer will also be presented. Overall, we demonstrate that magnetic polymer nanocomposite films are excellent candidates for EMI suppression applications. Work supported by NSF through Grant No. ECS 0140047

  1. TbxBi1-xFeO3 nanoparticulate multiferroics fabricated by micro-emulsion technique: Structural elucidation and magnetic behavior evaluation

    NASA Astrophysics Data System (ADS)

    Anwar, Zobia; Azhar Khan, Muhammad; Mahmood, Azhar; Asghar, M.; Shakir, Imran; Shahid, Muhammad; Bibi, Ismat; Farooq Warsi, Muhammad

    2014-04-01

    Tb-doped BiFeO3 multiferroics nanoparticles fabricated via micro-emulsion route were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fully characterized TbxBi1-xFeO3 nanoparticles were then subjected to magnetic behavior evaluation for various technological applications. The thermogravimetric analysis (TGA) conducted in the range 25-1000 °C predicted the temperature (~960 °C) for phase formation. XRD estimated the crystallite size 30-47 nm, while the particles size estimated by SEM was found (80-120 nm). The XRD data confirmed the rhombohedral (space group R3c) phase with average cell volume 182.66 Å3 (for BiFeO3). Various other physical parameters like bulk density, X-ray density and porosity were also determined from the XRD data and found in agreement with theoretical predictions. The magnetic studies showed that as Bi3+ was substituted by Tb3+, all magnetic parameters were altered. The maximum saturation magnetization (Ms) (0.6691 emug-1) was exhibited by Tb0.02Bi0.98FeO3 while the Tb0.00Bi1.00Fe1.00O3 showed the maximum (549 Oe) coercivity. The evaluated magnetic behavior categorized these materials as soft magnetic materials that may be useful for fabricating advanced technological applications.

  2. Nanostructured lithium oxide-hematite magnetic oxide semiconductors

    NASA Astrophysics Data System (ADS)

    Sorescu, Monica; Bushunow, Vasilii; Diamandescu, Lucian; Tolea, Felicia; Valeanu, Mihaela; Xu, Tianhong

    2015-03-01

    The study aims at exploring the formation of magnetic oxide semiconductors at the nanoscale, which is of crucial importance for catalysis, sensing and electrochemical applications. xLi2O-(1-x)alpha-Fe2O3(x = 0.1, 0.3, 0.5, and 0.7) nanoparticle systems were successfully synthesized by mechanochemical activation of Li2O and alpha-Fe2O3 mixtures for 0-12 hours of ball milling time. X-ray powder diffraction (XRD), Mossbauer spectroscopy and magnetic measurements were used to study the phase evolution. Rietveld refinement of the XRD patterns yielded the values of the particle size as function of composition and milling times. The Mossbauer studies showed that the spectrum of the mechanochemically activated composites evolved from a sextet for hematite to sextets and a doublet upon duration of the milling process with lithium oxide. Magnetic measurements recorded at 5 K to room temperature (RT) in an applied magnetic field of 50,000 Oe showed that the magnetization of the milled samples is larger at low temperatures than at RT and increases with decreasing particle size. Zero field cooling measurements made possible the determination of the blocking temperatures of the specimens as function of ball milling time and evidenced the occurrence of superparamagnetism in the studied samples. NSF-DMR-0854794.

  3. Magnetic investigations

    SciTech Connect

    Bath, G.D.; Jahren, C.E.; Rosenbaum, J.G. [Geological Survey, Denver, CO (USA); Baldwin, M.J. [Fenix and Scisson, Inc., Mercury, NV (USA)

    1983-12-31

    Air and ground magnetic anomalies in the Climax stock area of the NTS help define the gross configuration of the stock and detailed configuration of magnetized rocks at the Boundary and Tippinip faults that border the stock. Magnetizations of geologic units were evaluated by measurements of magnetic properties of drill core, minimum estimates of magnetizations from ground magnetic anomalies for near surface rocks, and comparisons of measured anomalies with anomalies computed by a three-dimensional forward program. Alluvial deposits and most sedimentary rocks are nonmagnetic, but drill core measurements reveal large and irregular changes in magnetization for some quartzites and marbles. The magnetizations of quartz monzonite and granodiorite near the stock surface are weak, about 0.15 A/m, and increase at a rate of 0.00196 A/m/m to 1.55 A/m, at depths greater than 700 m (2300 ft). The volcanic rocks of the area are weakly magnetized. Aeromagnetic anomalies 850 m (2800 ft) above the stock are explained by a model consisting of five vertical prisms. Prisms 1, 2, and 3 represent the near surface outline of the stock, prism 4 is one of the models developed by Whitehill (1973), and prism 5 is modified from the model developed by Allingham and Zietz (1962). Most of the anomaly comes from unsampled and strongly-magnetized deep sources that could be either granite or metamorphosed sedimentary rocks. 48 refs., 23 figs., 3 tabs.

  4. Structural and magnetic properties of TM-SiO2 (TM = Fe, Co, Ni) films

    NASA Astrophysics Data System (ADS)

    Socolovsky, L. M.; Denardin, J. C.; Brandl, A. L.; Knobel, M.; Zhang, X. X.

    2003-05-01

    TMx-(SiO2)1-x (TM=Fe, Co, Ni) thin films were prepared in a wide concentration range (0.35 ?x?1). Structure was studied with transmission electron microscopy (TEM), X-ray diffraction (XRD) and small angle X-ray scattering (SAXS). Magnetic and magnetotransport properties were investigated by means of magnetization and Hall effect measurements. TEM images display nanometric spherical structures embedded in a SiO2 amorphous matrix, with typical sizes increasing from 3 to 5nm when TM volume concentration x is increased. SAXS measurements indicate a complex structure formed by nanosized objects. XRD measurements show that the structure is composed by amorphous SiO2 and TM crystallites. Slightly above the percolation threshold all samples display giant Hall effect. The observed magnetic properties are dependent on x, and display an evolution resulting from the progressive increase of the mean particle size.

  5. Adsorptive removal of heavy metals by magnetic nanoadsorbent: an equilibrium and thermodynamic study

    NASA Astrophysics Data System (ADS)

    Shirsath, D. S.; Shirivastava, V. S.

    2015-01-01

    An efficient and new magnetic nanoadsorbent photocatalyst was fabricated by co-precipitation technique. This research focuses on understanding metal removal process and developing a cost-effective technology for treatment of heavy metal-contaminated industrial wastewater. In this investigation, magnetic nanoadsorbent has been employed for the removal of Zn(II) ions from aqueous solutions by a batch adsorption technique. The adsorption equilibrium data fitted very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Zn(II) ions adsorption onto the magnetic nanoadsorbents indicated that the adsorption was spontaneous, endothermic and physical in nature. Surface morphology of magnetic nanoadsorbent by scanning electron microscopy (SEM) and elemental analysis by EDX technique. The structural and photocatalytic properties of magnetic nanoadsorbent were characterized using X-ray diffraction (XRD) and FTIR techniques. Also, the magnetic properties of synthesized magnetic nanoadsorbent were determined by vibrating spinning magnetometer (VSM).

  6. XRD line-broadening characteristics of M-oxides (M = Mg, Mg-Al, Y, Fe) nanoparticles produced by coprecipitation method

    SciTech Connect

    Pratapa, S.; Susanti, L.; Insany, Y. A. S.; Alfiati, Z.; Hartono, B.; Mashuri,; Triwikantoro; Baqiya, M. A.; Purwaningsih, S.; Yahya, E.; Darminto [Department of Physics, Institute of Technology Sepuluh November (ITS), Jl. Arief Rahman Hakim, Surabaya, Indonesia 60111 (Indonesia); Taufiq, Ahmad; Fuad, Abdullah [Department of Physics, State University of Malang, Jl. Surabaya, Malang, Indonesia 60111 (Indonesia)

    2010-10-24

    Simple coprecipitation method has been used to produce nanoparticles of MgO (magnesia), MgO{center_dot}Al{sub 2}O{sub 3}(spinel), Y{sub 2}O{sub 3}(yttria) and Fe{sub 3}O{sub 4}(ferrite). The raw materials were, in respective, magnesium powder, magnesium and aluminium powders, ytrria powder, and natural sand. The coprecipitation included the use of suitable acid and base to dissolve the powders or sand and to produce precipitates, as well as the use of water to wash and purify the precipitates, and drying at relatively low temperatures, namely lower than 100 deg. C, followed by heating at 450 deg. C, 750 deg. C, 600 deg. C and 200 deg. C to produce magnesia, spinel, yttria and ferrite nanopowders, respectively. X-ray diffractometry was used to characterise the purity and nanocrystallinity of the final powders. It was found qualitatively that the powders were of high purity. Further line-broadening analysis using single-line and Rietveld-based softwares was performed to reveal the nanocrystallinity of the powders. Different line breadth values were found for the powders, indicating different crystallite sizes. It was also found that, particularly for spinel and yttria, the diffraction peaks exhibited 'longer' tails, indicating broader crystallite size distribution. The average crystallite size for the powders ranged from 3 to 70 nm. The results could then be used as 'fingerprints' for nanocrystallinity using x-ray diffractometry. The XRD crystallite sizes for yttria and ferrite nanocrystals are in fair agreement with their counterparts from electron microscopy observation.

  7. Adsorption and Separation of Light Gases on an Amino-Functionalized Metal–Organic Framework: An Adsorption and In Situ XRD Study

    SciTech Connect

    Couck S.; Stavitski E.; Gobehiya, E.; Kirschhock, C.E.A.; Serra-Crespo, P.; Juan-Alcaniz, J.; Martinez Joaristi, A.; Gascon, J.; Kapteijn, F.; Baron, G. V.; Denayer J.F.M.

    2012-02-29

    The NH{sub 2}-MIL-53(Al) metal-organic framework was studied for its use in the separation of CO{sub 2} from CH{sub 4}, H{sub 2}, N{sub 2} C{sub 2}H{sub 6} and C{sub 3}H{sub 8} mixtures. Isotherms of methane, ethane, propane, hydrogen, nitrogen, and CO{sub 2} were measured. The atypical shape of these isotherms is attributed to the breathing properties of the material, in which a transition from a very narrow pore form to a narrow pore form and from a narrow pore form to a large pore form occurs, depending on the total pressure and the nature of the adsorbate, as demonstrated by in-situ XRD patterns measured during adsorption. Apart from CO{sub 2}, all tested gases interacted weakly with the adsorbent. As a result, they are excluded from adsorption in the narrow pore form of the material at low pressure. CO{sub 2} interacted much more strongly and was adsorbed in significant amounts at low pressure. This gives the material excellent properties to separate CO{sub 2} from other gases. The separation of CO{sub 2} from methane, nitrogen, hydrogen, or a combination of these gases has been demonstrated by breakthrough experiments using pellets of NH{sub 2}-MIL-53(Al). The effect of total pressure (1-30 bar), gas composition, temperature (303-403 K) and contact time has been examined. In all cases, CO{sub 2} was selectively adsorbed, whereas methane, nitrogen, and hydrogen nearly did not adsorb at all. Regeneration of the adsorbent by thermal treatment, inert purge gas stripping, and pressure swing has been demonstrated. The NH{sub 2}-MIL-53(Al) pellets retained their selectivity and capacity for more than two years.

  8. Synthesis and detection the oxidization of Co cores of Co@SiO2 core-shell nanoparticles by in situ XRD and EXAFS.

    PubMed

    Zhang, Kunhao; Zhao, Ziyan; Wu, Zhonghua; Zhou, Ying

    2015-01-01

    In this paper, the Co@SiO2 core-shell nanoparticles were prepared by the sol-gel method. The oxidization of Co core nanoparticles was studied by the synchrotron radiation-based techniques including in situ X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) up to 800°C in air and N2 protection conditions, respectively. It was found that the oxidization of Co cores is undergoing three steps regardless of being in air or in N2 protection condition. In the first step ranging from room temperature to 200°C, the Co cores were dominated by Co(0) state as well as small amount of Co(2+) ions. When temperature was above 300°C, the interface between Co cores and SiO2 shells was gradually oxidized into Co(2+), and the CoO layer was observed. As the temperature increasing to 800°C, the Co cores were oxidized to Co3O4 or Co3O4/CoO. Nevertheless, the oxidization kinetics of Co cores is different for the Co@SiO2 in air and N2 gas conditions. Generally, the O2 in the air could get through the SiO2 shells easily onto the Co core surface and induce the oxidization of the Co cores due to the mesoporous nature of the SiO2 shells. However, in N2 gas condition, the O atoms can only be from the SiO2 shells, so the diffusion effect of O atoms in the interface between Co core and SiO2 shell plays a key role. PMID:25852334

  9. Synthesis and detection the oxidization of Co cores of Co@SiO2 core-shell nanoparticles by in situ XRD and EXAFS

    NASA Astrophysics Data System (ADS)

    Zhang, Kunhao; Zhao, Ziyan; Wu, Zhonghua; Zhou, Ying

    2015-02-01

    In this paper, the Co@SiO2 core-shell nanoparticles were prepared by the sol-gel method. The oxidization of Co core nanoparticles was studied by the synchrotron radiation-based techniques including in situ X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) up to 800°C in air and N2 protection conditions, respectively. It was found that the oxidization of Co cores is undergoing three steps regardless of being in air or in N2 protection condition. In the first step ranging from room temperature to 200°C, the Co cores were dominated by Co0 state as well as small amount of Co2+ ions. When temperature was above 300°C, the interface between Co cores and SiO2 shells was gradually oxidized into Co2+, and the CoO layer was observed. As the temperature increasing to 800°C, the Co cores were oxidized to Co3O4 or Co3O4/CoO. Nevertheless, the oxidization kinetics of Co cores is different for the Co@SiO2 in air and N2 gas conditions. Generally, the O2 in the air could get through the SiO2 shells easily onto the Co core surface and induce the oxidization of the Co cores due to the mesoporous nature of the SiO2 shells. However, in N2 gas condition, the O atoms can only be from the SiO2 shells, so the diffusion effect of O atoms in the interface between Co core and SiO2 shell plays a key role.

  10. Development of an x-ray diffraction camera used in magnetic fields up to 10 T

    NASA Astrophysics Data System (ADS)

    Mitsui, Yoshifuru; Koyama, Keiichi; Takahashi, Kohki; Watanabe, Kazuo

    2011-12-01

    A high-field x-ray diffraction (HF-XRD) camera was developed to observe structural changes of magnetic materials in magnetic fields up to 10 T. The instrument mainly consists of a Debye-Scherrer-type camera with a diameter of 80.1 mm, a 10-T cryocooled superconducting magnet with a 100-mm room-temperature bore, an x-ray source, a power supply, and a chiller for the x-ray source. An x-ray detector (image plate) in the HF-XRD camera can be taken out and inserted into the magnet without changing the sample position. The performance of the instrument was tested by measuring the HF-XRD for silicon and ferromagnetic MnBi powders. A change of x-ray diffraction pattern was observed due to the magnetic orientation of MnBi, showing that the instrument is useful for studying field-induced orientation processes and structural properties of field-controlled materials.

  11. Development of an x-ray diffraction camera used in magnetic fields up to 10 T.

    PubMed

    Mitsui, Yoshifuru; Koyama, Keiichi; Takahashi, Kohki; Watanabe, Kazuo

    2011-12-01

    A high-field x-ray diffraction (HF-XRD) camera was developed to observe structural changes of magnetic materials in magnetic fields up to 10 T. The instrument mainly consists of a Debye-Scherrer-type camera with a diameter of 80.1 mm, a 10-T cryocooled superconducting magnet with a 100-mm room-temperature bore, an x-ray source, a power supply, and a chiller for the x-ray source. An x-ray detector (image plate) in the HF-XRD camera can be taken out and inserted into the magnet without changing the sample position. The performance of the instrument was tested by measuring the HF-XRD for silicon and ferromagnetic MnBi powders. A change of x-ray diffraction pattern was observed due to the magnetic orientation of MnBi, showing that the instrument is useful for studying field-induced orientation processes and structural properties of field-controlled materials. PMID:22225246

  12. Magnet Healing?

    NASA Astrophysics Data System (ADS)

    Finegold, Leonard

    2000-03-01

    Many people are convinced that static magnets—applied to their skin—will heal ills, and many businesses sell such magnets. The biophysics of such healing was reviewed [1] together with the general biophysics of static fields. Birds and insects do use the earth’s magnetic field for navigation. While insect and frog egg development can clearly be influenced by high fields (7 T and 17 T respectively), there is no experimental evidence that small magnetic fields (of less than 0.5 T) might heal, and much evidence that they cannot heal. A puzzle to the physics community is: How to show laypersons that simple magnets (very probably) do not heal, however attractive that idea might be. [1] L. Finegold, The Physics of "Alternative Medicine": Magnet Therapy, The Scientific Review of Alternative Medicine 3:26-33 (1999).

  13. Planetary Magnetism

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.

    2007-01-01

    The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

  14. Magnetically separable nanocomposites with photocatalytic activity under visible light for the selective transformation of biomass-derived platform molecules

    EPA Science Inventory

    Novel magnetically separable TiO2-guanidine-(Ni,Co)Fe2O4 nanomaterials were prepared and characterised by a series of techniques including XRD, SEM, TEM, N2 physisorption as well as XPS and subsequently tested for their photocatalytic activities in the selective transformation of...

  15. Magnetic nanoparticles

    Microsoft Academic Search

    R. H Kodama

    1999-01-01

    Intrinsic properties of magnetic nanoparticles are reviewed, with special emphasis on the effects of finite size on zero-temperature spin ordering, magnetic excitations, and relaxation. Effects on zero-temperature spin ordering include moment enhancement due to band narrowing in 3d transition metal particles, surface spin disorder in ferrite particles, and multi-sublattice states in antiferromagnetic oxide particles. Magnetic excitations include discretized spin wave

  16. Structural and magnetic properties of nanocrystalline nickel-rich Fe-Ni alloy powders prepared via hydrazine reduction

    NASA Astrophysics Data System (ADS)

    Xu, Zhichao; Jin, Chuangui; Xia, Ailin; Zhang, Junyan; Zhu, Guohui

    2013-06-01

    Nickel-rich Fe-Ni alloy nanoparticles with different compositions were prepared by solution reduction using hydrazine as reductant. The phase composition, morphologies and magnetic properties of as-prepared and annealed samples were characterized by an X-ray diffractionmeter (XRD), a scanning electron microscope (SEM) and a vibrating sample magnetometer (VSM), respectively. XRD results show that all the samples exhibit a single phase with face-centered cubic structure before and after annealing. SEM images show that the as-prepared spherical particles are composed of smaller crystallites. VSM results indicate that the saturation magnetization decreases obviously with the increase of nickel content, while it increases with the annealing temperature. In addition, the samples transform from a half hard magnetic behavior to a typical soft magnetic behavior with the increase of annealing temperature.

  17. Magnetic Fluids

    NSDL National Science Digital Library

    2014-09-18

    In this fun, engaging activity, students are introduced to a unique type of fluid—ferrofluids—whose shape can be influenced by magnetic fields! Students act as materials engineers and create their own ferrofluids. They are challenged to make magnetic ink out of ferrofluids and test their creations to see if they work. Concurrently, they learn more about magnetism, surfactants and nanotechnology. As they observe fluid properties as a standalone-fluid and under an imposed magnetic field, they come to understand the components of ferrofluids and their functionality.

  18. Planetary magnetism

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1980-01-01

    Planetary spacecraft have now probed the magnetic fields of all the terrestrial planets, the moon, Jupiter, and Saturn. These measurements reveal that dynamos are active in at least four of the planets, Mercury, the earth, Jupiter, and Saturn but that Venus and Mars appear to have at most only very weak planetary magnetic fields. The moon may have once possessed an internal dynamo, for the surface rocks are magnetized. The large satellites of the outer solar system are candidates for dynamo action in addition to the large planets themselves. Of these satellites the one most likely to generate its own internal magnetic field is Io.

  19. Strange Magnetism

    E-print Network

    Thomas R. Hemmert; Ulf-G. Meissner; Sven Steininger

    1998-11-09

    We present an analytic and parameter-free expression for the momentum dependence of the strange magnetic form factor of the nucleon and its corresponding radius which has been derived in Heavy Baryon Chiral Perturbation Theory. We also discuss a model-independent relation between the isoscalar magnetic and the strange magnetic form factors of the nucleon based on chiral symmetry and SU(3) only. These limites are used to derive bounds on the strange magnetic moment of the proton from the recent measurement by the SAMPLE collaboration.

  20. Magnetic shielding

    DOEpatents

    Kerns, John A. (Livermore, CA); Stone, Roger R. (Walnut Creek, CA); Fabyan, Joseph (Livermore, CA)

    1987-01-01

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  1. Magnetic materials

    NASA Astrophysics Data System (ADS)

    1985-03-01

    The report describes the fundamental role that magnetic materials play in many of the electrical and electronic systems used by modern society. It reviews the status of magnetic materials in their current engineering applications and identifies technical issues whose resolution would lead to improved performance in such applications as well as for new applications of these materials. The report recommends more research in the areas of rare-earth permanent magnets, amorphous magnetic materials and recording media and lists a number of scientific challenges.

  2. HRTEM Imaging of Atoms at Sub-Angstrom Resolution

    SciTech Connect

    O'Keefe, Michael A.; Allard, Lawrence F.; Blom, Douglas A.

    2005-04-06

    John Cowley and his group at Arizona State University pioneered the use of transmission electron microscopy (TEM) for high-resolution imaging. Images were achieved three decades ago showing the crystal unit cell content at better than 4 Angstrom resolution. This achievement enabled researchers to pinpoint the positions of heavy atom columns within the unit cell. Lighter atoms appear as resolution is improved to sub-Angstrom levels. Currently, advanced microscopes can image the columns of the light atoms (carbon, oxygen, nitrogen) that are present in many complex structures, and even the lithium atoms present in some battery materials. Sub-Angstrom imaging, initially achieved by focal-series reconstruction of the specimen exit surface wave, will become common place for next-generation electron microscopes with CS-corrected lenses and monochromated electron beams. Resolution can be quantified in terms of peak separation and inter-peak minimum, but the limits imposed on the attainable resolution by the properties of the micro-scope specimen need to be considered. At extreme resolution the ''size'' of atoms can mean that they will not be resolved even when spaced farther apart than the resolution of the microscope.

  3. Structural transformation of vapor grown carbon nanofibers studied by HRTEM

    Microsoft Academic Search

    Joseph G. Lawrence; Lesley M. Berhan; Arunan Nadarajah

    2008-01-01

    Vapor grown carbon nanofibers have been extensively manufactured and investigated in recent years. In this study commercially\\u000a available vapor grown carbon nanofibers subjected to different processing and post processing conditions were studied employing\\u000a high resolution TEM images. The analysis showed that the fibers consist primarily of conical nanofibers, but can contain a\\u000a significant amount of bamboo nanofibers. Most conical nanofibers

  4. Glass forming ability and microstructure of hard magnetic Nd 60Al 20Fe 20 glass forming alloy

    Microsoft Academic Search

    L. Xia; S. S. Fang; C. L. Jo; Y. D. Dong

    2006-01-01

    Glass forming ability (GFA), magnetic properties and microstructure of Nd60Al20Fe20 as-cast rod were investigated and further compared with Nd60Al10Fe30 glass forming alloy. The rod prepared by suction casting with a diameter of 3mm exhibits the typical amorphous nature in XRD pattern, distinct glass transition in DSC traces and hard magnetic properties. It is found that the diameter of cast Nd60Al20Fe20

  5. Fe\\/Sr ratio effect on magnetic properties of strontium ferrite powders synthesized by microwave-induced combustion process

    Microsoft Academic Search

    Yen-Pei Fu; Cheng-Hsiung Lin

    2005-01-01

    Strontium hexaferrite nano-particles were successfully synthesized by microwave-induced combustion process. Magnetic properties of strontium ferrite powders with Fe\\/Sr ratios varying from 11 to 12 and different annealing temperatures range of 850 to 1050°C were studied. The resultant powders were investigated by XRD, TEM, SEM, VSM, TG\\/DTA, and surface area measurement. The optimum magnetic properties of strontium ferrite powders were as

  6. Biocellulose-based flexible magnetic paper

    NASA Astrophysics Data System (ADS)

    Barud, H. S.; Tercjak, A.; Gutierrez, J.; Viali, W. R.; Nunes, E. S.; Ribeiro, S. J. L.; Jafellici, M.; Nalin, M.; Marques, R. F. C.

    2015-05-01

    Biocellulose or bacterial cellulose (BC) is a biocompatible (nano) material produced with a three-dimensional network structure composed of microfibrils having nanometric diameters obtained by the Gluconacetobacter xylinus bacteria. BC membranes present relatively high porosity, allowing the incorporation or synthesis in situ of inorganic nanoparticles for multifunctional applications and have been used as flexible membranes for incorporation of magnetic nanocomposite. In this work, highly stable superparamagnetic iron oxide nanoparticles (SPION), functionalized with polyethylene glycol (PEG), with an average diameter of 5 nm and a saturation magnetization of 41 emu/g at 300 K were prepared. PEG-Fe2O3 hybrid was dispersed by mixing a pristine BC membrane in a stable aqueous dispersion of PEG-SPION. The PEG chains at PEG-SPION's surface provide a good permeability and strong affinity between the BC chains and SPION through hydrogen-bonding interactions. PEG-SPION also allow the incorporation of higher content of nanoparticles without compromising the mechanical properties of the nanocomposite. Structural and magnetic properties of the composite have been characterized by XRD, SEM, energy-dispersive X-ray spectroscopy (EDX), magnetization, Raman spectroscopy, and magnetic force microscopy.

  7. Structural studies of GMR magnetic multilayers and spin-valves grown by DC sputtering

    NASA Astrophysics Data System (ADS)

    Geng, Hong

    The structures and growth characteristics of sputtered GMR magnetic multilayers and spin-valves have been characterized using conventional and high resolution transmission electron microscopy (CTEM and HRTEM). The first part of this dissertation focused on the characterization of polycrystalline Cu/Py (permalloy(TM)), Ag/Py, and Cu/CoZr spin-valves. For the Cu/Py spin-valves, structures with different Py thicknesses sputtered at different temperatures were examined. All of the spin-valves displayed polycrystalline structures with columnar grains. The grains grew on close packed planes ({111} in the bcc Nb contacts and {110} in the fcc Cu, FeMn, and Py spin-valve layers) taking up a near Kurdjumov-Sachs {111}fcc//{110}bcc;<110> fcc//<111>bcc orientation relationship. FFT analysis and HRTEM image simulations indicate that in some of the columnar grains, the Cu, FeMn, and Py regions take up non-equilibrium bcc structures, regardless of differences in layer thicknesses and sputtering temperatures. For the Ag/Py spin-valves, in addition to the expected polycrystalline morphology, in one instance an epitaxial single crystal Ag layer was discovered when the spin-valve was grown directly on a Si substrate. HREDS has shown that this single crystal (epitaxial) layer is likely composed of Ag and In in a 4:1 atomic ratio. In all of the other Ag/Py spin-valve samples, polycrystalline morphologies were consistently observed regardless of the substrate. For the Cu/CoZr spin-valves, CTEM observations of two spin-valves revealed that both samples are polycrystalline with columnar grains similar to the morphologies observed in Cu/Py and Ag/Py spin-valves. The second part of this dissertation is focused on determining the correct parameters for growing a high quality Cu buffer layer on an epitaxial Nb contact. CTEM observations demonstrate that the quality of epitaxial growth of Cu buffer layers depends strongly on deposition temperatures and post annealing. High quality epitaxial Cu buffer layers were obtained when the Cu layer was grown at low temperatures (100°C and 150°C) without post annealing. Diffraction patterns of multilayers show that twin variants appear in epitaxial Cu and Py layers, consistent with electron backscatter patterns (EBSP) results from thick films. HRTEM images reveal that the Cu buffer layer grown at 150°C appears as twin variants with two stacking sequences of {111} fcc planes. A three-layer periodic contrast observed in the Py layer can be rationalized based on overlapped twins along [110] with {111} twin planes.

  8. Magnetic shielding

    DOEpatents

    Kerns, J.A.; Stone, R.R.; Fabyan, J.

    1985-02-12

    A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

  9. Influence of Au addition on magnetic properties of iron oxide in a silica-phosphate glass matrix

    NASA Astrophysics Data System (ADS)

    Sharma, K.; Prajapat, C. L.; Meena, Sher Singh; Singh, M. R.; Yusuf, S. M.; Montagne, L.; Kothiyal, G. P.

    2013-11-01

    The influence of gold particle addition on structural and magnetic ordering of iron oxide in a glass matrix was studied. The silica-phosphate glasses containing iron oxide and Au were prepared by the melt quench technique. Evolution of crystalline phases was studied by X-ray diffraction (XRD). Magnetic properties were investigated by means of a Superconducting Quantum Interference Device (SQUID) magnetometer and room temperature Mössbauer spectroscopy. The microstructure exhibited the formation of 30-40 nm size particles. The samples showed the formation of magnetite and hematite as major crystalline phases. Magnetic studies revealed the relaxation of magnetic particles. Blocking temperature of investigated sample increased with an increase of Au content implying an increase in the strength of magnetic interactions. Mössbauer spectroscopy has shown the presence of both doublets and magnetic sextets. The magnetization value increased as Au content was increased, which is attributed to the increase in magnetic and structural ordering.

  10. Magnetic nanotubes

    SciTech Connect

    Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  11. Magnetic silica nanotubes: synthesis, drug release, and feasibility for magnetic hyperthermia.

    PubMed

    Chen, Xuecheng; Klingeler, Rüdiger; Kath, Matthias; El Gendy, Ahmed A; Cendrowski, Krzysztof; Kalenczuk, Ryszard J; Borowiak-Palen, Ewa

    2012-04-01

    A new kind of silica nanotube with incorporated ?-Fe(2)O(3) nanoparticles has been successfully prepared through sol-gel processes. Hematite particles supported on carbon nanotubes served as templates for the fabrication of the magnetic silica nanotubes. The obtained nanostructures consisting of magnetic Fe(2)O(3) nanoparticles protected by a silica shell were fully characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), N(2) sorption and desorption, and magnetization studies. The hollow inner space and the magnetic functionalization render the material promising for applications in biology and medicine. This is underlined by studies in alternating magnetic fields which show a significant heating effect, i.e., the feasibility for applications in hyperthermia therapies. In addition, the material exhibits enhanced drug-loading capacity which is demonstrated by loading with rhodamine B molecules as drugs and corresponding release experiments. The results show that magnetic silica nanotubes can be straightforwardly synthesized and have a great potential as a multifunctional drug carrier system. PMID:22486255

  12. Synthesis, characterization and magnetic properties of Cr-substituted Co-Zn ferrites nanopowders

    NASA Astrophysics Data System (ADS)

    Gabal, M. A.; Al Angari, Y. M.; Al-Agel, F. A.

    2013-03-01

    Nano-crystalline ferrites; Co0.9Zn0.1Fe2-xCrxO4 (where x = 0-1) have been synthesized through thermal decomposition reaction of their respective oxalates. The effect of Cr3+ ion substitution on the structural and magnetic properties was studied. Differential thermal analysis-thermogravimetry (DTA-TG) techniques were used to characterize the oxalates decomposition reaction and following ferrite formation. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and vibrating scanning magnetometry (VSM) were used to characterize the structural, morphological and magnetic properties. XRD revealed single-phase cubic spinels. Both crystallite size and lattice parameter decreases with increasing Cr-content. FT-IR spectral studies confirmed the suggested cation distribution estimated through XRD measurements. TEM image showed agglomerated spherical nanoparticles with size of about 20 nm. The gradual decrease in the saturation magnetization, estimated through VSM measurements, with increasing Cr-content suggests the preferential occupation of Cr3+ ions in the octahedral sites and confirmed the suggested cation distribution while, the decrease in the coercivity values indicating the loss of magneto-crystalline anisotropy. The decrease in the Curie temperatures obtained from dc-magnetic susceptibility with the increasing chromium can be attributed to the decrease in the A-B exchange interaction.

  13. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  14. Magnetic disk

    NASA Technical Reports Server (NTRS)

    Mallinson, John C.

    1992-01-01

    Magnetic disk recording was invented in 1953 and has undergone intensive development ever since. As a result of this 38 years of development, the cost per byte and the areal density have halved and doubled respectively every 2-2 1/2 years. Today, the cost per byte is lower than 10(exp -6) dollars per byte and area densities exceed 100 10(exp 6) bits per square inch. In this talk, the recent achievements in magnetic disk recording are first surveyed briefly. Then, the principal areas of current technical development are outlined. Finally, some comments are made about the future of magnetic disk recording.

  15. Magnetic disk

    NASA Technical Reports Server (NTRS)

    Mallinson, John C.

    1991-01-01

    Magnetic disk recording was invented in 1953 and has undergone intensive development ever since. As a result of this 38 years of development, the cost per byte and the areal density has halved and doubled, respectively every 2 to 2 1/2 years. Today, the cost per byte is lower than 10(exp -6) dollars per byte and area densities exceed 100 x 10(exp 6) bits per square inch. The recent achievements in magnetic disk recording will first be surveyed briefly. Then the principal areas of current technical development will be outlined. Finally, some comments will be made about the future of magnetic disk recording.

  16. Lunar magnetism

    NASA Technical Reports Server (NTRS)

    Hood, L. L.; Sonett, C. P.; Srnka, L. J.

    1984-01-01

    Aspects of lunar paleomagnetic and electromagnetic sounding results which appear inconsistent with the hypothesis that an ancient core dynamo was the dominant source of the observed crustal magnetism are discussed. Evidence is summarized involving a correlation between observed magnetic anomalies and ejecta blankets from impact events which indicates the possible importance of local mechanisms involving meteoroid impact processes in generating strong magnetic fields at the lunar surface. A reply is given to the latter argument which also presents recent evidence of a lunar iron core.

  17. Magnetic Trapping

    NSDL National Science Digital Library

    Mendez, J.

    This set of five web pages provides a non-mathematical introduction to the motion of charged particles in magnetic fields. These pages describe the "guiding center motion" which determines the motion of ions and electrons trapped in the Earth's magnetic field and in laboratory plasma devices. Also covered are gyration and mirroring, adiabatic invariance and drifts due to an electric field and gradients in the magnetic field intensity. This is part of the work "The Exploration of the Earth's Magnetosphere". A Spanish translation is available.

  18. Structural, optical and magnetic characterization of Cu-doped ZnO nanoparticles synthesized using solid state reaction method

    Microsoft Academic Search

    R. Elilarassi; G. Chandrasekaran

    2010-01-01

    Polycrystalline undoped and Cu-doped Zinc oxide (Zn0.98Cu0.02O) nanocrystals were successfully synthesized by solid-state reaction method. The micro structural, optical and magnetic properties\\u000a have been characterized using powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive analysis\\u000a using X-rays (EDAX), UV–Visible spectroscopy, Photoluminescence, Vibrating sample magnetometer and Electron paramagnetic resonance\\u000a spectroscopy. XRD pattern reveals that the samples possess hexagonal wurtzite

  19. Magnetic properties of hydrogen-included TiZrNiPd quasicrystals.

    PubMed

    Shin, Hongsik; Lee, Sang-Hwa; Jo, Youngsoo; Kim, Jae-Yong

    2012-07-01

    Quasicrystals prepared by rapid quenching of Pd-added TiZrNi ingots were hydrogenated, and effects of hydrogen for magnetic properties were compared with the unhydrogenated ones under magnetic fields from -10000 to 10000 Oe. The magnetization values obtained from vibrating sample magnetometer (VSM) were analyzed with the combination of powder X-ray diffraction (XRD) data. While its contribution is larger than that of Pd, hydrogen decreases the magnetic moments of both Pd-doped and undoped quasicrystals. As increasing the amount of absorbed hydrogen which is represented by H/M (hydrogen to host metal atom ratio) values from 0 to 1.19, the magnetization values of Ti53Zr27Ni20 quasicrystals measured at 10000 Oe significantly decreased from 0.301 to 0.212 emu/g. A careful analysis of XRD data demonstrated that the reduced interactions of magnetic dipole moments between Ni atoms, as the product of the expansion of the quasilattice constants after hydrogenation, are responsible for the decreased magnetization values in hydrogenated TiZrNiPd quasicrystal samples. PMID:22966713

  20. Magnetic monopoles

    SciTech Connect

    Fryberger, D.

    1984-12-01

    In this talk on magnetic monopoles, first the author briefly reviews some historical background; then, the author describes what several different types of monopoles might look like; and finally the author discusses the experimental situation. 81 references.

  1. Synthesis and characterization of functional magnetic nanocomposites

    NASA Astrophysics Data System (ADS)

    Gass, J.; Sanders, J.; Srinath, S.; Srikanth, H.

    2006-03-01

    Magnetic nanoparticles and carbon nanotubes have been excellent functional materials that could be dispersed in polymer matrices for various applications. However, uniform dispersion of particles in polymers without agglomeration is quite challenging. We have fabricated PMMA/polypyrrole bilayer structures embedded with Fe3O4 magnetite nanoparticles synthesized using wet chemical synthesis. Agglomeration-free dispersion of nanoparticles was achieved by coating the particles with surfactants and by dissolving both the particles and PMMA in chlorobenzene. Structural characterization was done using XRD and TEM. Magnetic properties of the bilayer structures indicated superparamagnetic behavior that is desirable for RF applications as the magnetic losses are reduced. Our polymer nanocomposite bilayer films with conducting polymer coatings are potential candidates for tunable RF applications with integrated EMI suppression. We will also report on our studies of pumped ferrofluids flowing past carbon nanotubes that are arranged in microchannel arrays. Magnetization under various flow conditions is investigated and correlated with the hydrodynamic properties. This scheme provides a novel method of energy conversion and storage using nanocomposite materials.

  2. Investigation of the composition of historical and modern Italian papers by energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS).

    PubMed

    Manso, Marta; Carvalho, Maria Luisa; Queralt, Ignacio; Vicini, Silvia; Princi, Elisabetta

    2011-01-01

    In this work, a study concerning the composition of Italian papers from the seventeenth to the twentieth centuries was carried out using energy dispersive X-ray fluorescence spectrometry (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The analyzed samples consisted of papers employed for drawing, writing, printing, and absorbance. Observations carried out by SEM magnified the typical paper morphology. EDXRF in combination with XRD and SEM-EDS allowed the determination of calcite, gypsum, kaolin, talc, magnesite, and dolomite, used as fillers in the production of the papers studied herein. The inks present in the handwritten and printed papers, investigated by SEM-EDS and ?-EDXRF, were synthetic, Fe based, and iron gall inks. PMID:21211154

  3. Magnetic liposomes for colorectal cancer cells therapy by high-frequency magnetic field treatment.

    PubMed

    Hardiansyah, Andri; Huang, Li-Ying; Yang, Ming-Chien; Liu, Ting-Yu; Tsai, Sung-Chen; Yang, Chih-Yung; Kuo, Chih-Yu; Chan, Tzu-Yi; Zou, Hui-Ming; Lian, Wei-Nan; Lin, Chi-Hung

    2014-01-01

    In this study, we developed the cancer treatment through the combination of chemotherapy and thermotherapy using doxorubicin-loaded magnetic liposomes. The citric acid-coated magnetic nanoparticles (CAMNP, ca. 10 nm) and doxorubicin were encapsulated into the liposome (HSPC/DSPE/cholesterol?=?12.5:1:8.25) by rotary evaporation and ultrasonication process. The resultant magnetic liposomes (ca. 90 to 130 nm) were subject to characterization including transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), zeta potential, Fourier transform infrared (FTIR) spectrophotometer, and fluorescence microscope. In vitro cytotoxicity of the drug carrier platform was investigated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using L-929 cells, as the mammalian cell model. In vitro cytotoxicity and hyperthermia (inductive heating) studies were evaluated against colorectal cancer (CT-26 cells) with high-frequency magnetic field (HFMF) exposure. MTT assay revealed that these drug carriers exhibited no cytotoxicity against L-929 cells, suggesting excellent biocompatibility. When the magnetic liposomes with 1 ?M doxorubicin was used to treat CT-26 cells in combination with HFMF exposure, approximately 56% cells were killed and found to be more effective than either hyperthermia or chemotherapy treatment individually. Therefore, these results show that the synergistic effects between chemotherapy (drug-controlled release) and hyperthermia increase the capability to kill cancer cells. PMID:25246875

  4. Magnets 1: Magnetic Pick-ups

    NSDL National Science Digital Library

    This lesson provides students with an understanding that certain materials are attracted to magnets while others are not. It is the first in a two-lesson series on magnets. In Magnets 1: Magnetic Pick-ups, students will look at various objects, make predictions about whether they are magnetic, and then test their predictions. This exploration is an introductory activity to magnets and magnetism.

  5. Neutrino magnetic moment in a magnetized plasma

    E-print Network

    N. V. Mikheev; E. N. Narynskaya

    2010-11-08

    The contribution of a magnetized plasma to the neutrino magnetic moment is calculated. It is shown that only part of the additional neutrino energy in magnetized plasma connecting with its spin and magnetic field strength defines the neutrino magnetic moment. It is found that the presence of magnetized plasma does not lead to the considerable increase of the neutrino magnetic moment in contrast to the results presented in literature previously.

  6. Magnetism. Blowing magnetic skyrmion bubbles.

    PubMed

    Jiang, Wanjun; Upadhyaya, Pramey; Zhang, Wei; Yu, Guoqiang; Jungfleisch, M Benjamin; Fradin, Frank Y; Pearson, John E; Tserkovnyak, Yaroslav; Wang, Kang L; Heinonen, Olle; te Velthuis, Suzanne G E; Hoffmann, Axel

    2015-07-17

    The formation of soap bubbles from thin films is accompanied by topological transitions. Here we show how a magnetic topological structure, a skyrmion bubble, can be generated in a solid-state system in a similar manner. Using an inhomogeneous in-plane current in a system with broken inversion symmetry, we experimentally "blow" magnetic skyrmion bubbles from a geometrical constriction. The presence of a spatially divergent spin-orbit torque gives rise to instabilities of the magnetic domain structures that are reminiscent of Rayleigh-Plateau instabilities in fluid flows. We determine a phase diagram for skyrmion formation and reveal the efficient manipulation of these dynamically created skyrmions, including depinning and motion. The demonstrated current-driven transformation from stripe domains to magnetic skyrmion bubbles could lead to progress in skyrmion-based spintronics. PMID:26067256

  7. Magnetic detection of magnetic monopoles

    SciTech Connect

    Trower, P.W.

    1983-09-01

    The idea of magnetic monopoles has a long history, but it wasn't until Dirac's demonstration that monopoles could explain charge quantization that the modern era began. Unfortunately, experiment did not oblige by finding any monopoles so for the next fifty years monopoles were only an interesting curiosity. When 't Hooft and Polyakov demonstrated that monopoles are an inevitable consequence of gauge theories currently being used to unify the electroweak (photon-lepton) and nuclear (quark) interactions, interest was quickened. Then a solitary, uncorroborated candidate event was found last spring at Stanford which indicated that magnetic monopoles might exist. However, the monopole abundance implied by the Stanford event is in clear contradiction to bounds on their number from astronomical data. Chief among the arsenal of detection techniques have been those that are uniquely magnetic. The authors review the monopole idea with emphasis on its magnetic detection.

  8. Enhancement of the magnetic properties of Al/La multiferroic

    NASA Astrophysics Data System (ADS)

    Ahmed, M. A.; Okasha, N.; Hussein, B.

    2012-08-01

    Nanosized multiferroic La1-xAlxFeO3 (0.00?x?0.20) samples were successfully synthesized by the citrate technique without subsequent heat treatment. All the prepared samples revealed single phase orthorhombic structure of space group Pbnm. XRD data revealed that the lattice parameters (a) decrease with increasing Al content. The magnetic susceptibility (?M) was enhanced significantly from 0.36 to 0.68 emu/g mole from LaFeO3 to La0.8Al0.2FeO3 respectively. The values of magnetization (M) and effective magnetic moment (?eff) were found to increase with increasing Al content. The enhancement of the physical and structural properties of the investigated multiferroic is possibly due to the changes in the lattice parameters, tolerance factor as well as crystallite size caused by aluminum substitution.

  9. Transferred hyperfine interaction and structure in LiMn2O4 and Li2MnO3 coexisting phases:mA XRD and 7Li NMR-MAS study

    Microsoft Academic Search

    Piercarlo Mustarelli; Vincenzo Massarotti; Marcella Bini; Doretta Capsoni

    1997-01-01

    X-ray diffraction (XRD) and 7MAS measurements have been performed on LiMn2O4 (lithium cationic fraction, x=0.333), Li2MnO3 (x=0.667), and the intermediate composition with x=0.40. The use of magic angle spinning produces complex manifolds of the spinning sidebands. The predominant interaction affecting the NMR spectrum is the transferred hyperfine coupling (TFHI) between the Mn ions and the Li spins. TFHI parameters are

  10. Temperature dependence of FMR spectrum of Fe3C magnetic agglomerates

    NASA Astrophysics Data System (ADS)

    Guskos, N.; Typek, J.; Maryniak, M.; Narkiewicz, U.; Arabczyk, W.; Kucharewicz, I.

    2005-01-01

    The sample of iron carbide has been prepared using carburisation of iron with ethylene/hydrogen mixture. After carburisation, the sample was characterized by using XRD and scanning electron microscopy. XRD revealed the presence of cementite phase only. The mean size of cementite crystallites was determined to be 46 nm. The FMR absorption signals have been investigated in the temperature range from liquid helium up to room temperature. The asymmetric, very broad and intense FMR line was registered and decomposed in two Lorentzian-shape components (low- and high-field). The main high-field component shifts toward low magnetic fields with decreasing temperature. At 75 K a phase transition was observed due to the freezing of the non-magnetic matrix. Additionally, the spin glass state was recorded below 30 K.

  11. Structural and magnetic properties of nano-NiFe2O4 prepared using green nanotechnology

    NASA Astrophysics Data System (ADS)

    Yehia, M.; Labib, Sh.; Ismail, S. M.

    2014-08-01

    Nanocrystalline spinel ferrite NiFe2O4 powders were synthesized by a novel green nanotechnology derivative of sol-gel method. The effect of preparation conditions on the particle size (D) and accordingly magnetic properties was investigated using X-ray powder diffraction (XRD), Mössbauer effect spectrometer (ME) and vibrating sample magnetometer (VSM). The obtained results were compared to samples prepared using a standard ceramic method and a sol-gel technique using a citric acid route. XRD measurements reflected the spinel structure of prepared samples. The results confirmed the critical dependence of the particle size on the preparation method and heat treatment. Mössbauer effect spectroscopy measurements indicated a strong impact of the particle size on the measured spectra. A gradual decrease of the hyperfine field with decreasing D was observed. Both the saturation magnetization MS and the coercivity Hc are found to be influenced by the decrease of the particle size.

  12. Permanent Bar Magnets

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about the basic properties of magnets and magnetism. Learners explore concepts such as magnetic fields and polarity, which form the basic ingredients of a study of Earth's magnetic field and the technology of magnetometers. Materials needed include bar magnets and paper clips. This is Activity 1 of Exploring Magnetism: A Teacher's Magnetism Activity Guide.

  13. Electric field control of magnetic phase transitions in Ni3V2ø8

    Microsoft Academic Search

    P. Kharel; C. Sudakar; A. B. Harris; R. Naik; G. Lawes

    2008-01-01

    In certain multiferroics, including Ni3V2O8, the ferroelectric order is induced by the magnetic structure, leading to the simultaneous onset of spin and charge ordering. We have prepared thin films of Ni3V2O8 by sputter deposition. Films annealed at 1000^0C crystallize with closely packed rod-like grains. XRD confirms that the films are single phase Ni3V2O8 and highly oriented along the b-axis. We

  14. Structural and magnetic studies on transition metal (Mn, Co) doped ZnO nanoparticles

    Microsoft Academic Search

    V. K. Sharma; M. Najim; A. K. Srivastava; G. D. Varma

    We report on the structural and magnetic properties of the nanocrystalline samples of Zn1?x(TM)xO (TM=Mn, Co and x=0.02, 0.05, 0.10) synthesized by chemical vapor deposition (CVD) method using different carrier gases i.e., Argon (Ar), Oxygen (O2) and Nitrogen (N2). X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies reveal wurtzite structure of pure ZnO in all the samples and particle

  15. Structure and magnetism of cobalt-doped ZnO thin films

    Microsoft Academic Search

    M. Ivill; S. J. Pearton; S. Rawal; L. Leu; P. Sadik; R. Das; A. F. Hebard; Matthew F Chisholm; John D Budai; David P. Norton

    2008-01-01

    The structure and magnetic properties of Co-doped ZnO films are discussed in relation to cobalt doping levels and growth conditions. Films were deposited by pulsed-laser deposition (PLD) from ZnO targets containing cobalt concentrations from 0 to 30 at.%. The structure of the films is examined by x-ray diffraction (XRD) and transmission electron microscopy (TEM), and optical absorption is used to

  16. Structural and magnetic studies of nanocrystalline Y2Ir2O7

    NASA Astrophysics Data System (ADS)

    Dwivedi, Vinod Kumar; Mukhopadhyay, Soumik

    2015-06-01

    In this paper, we discuss synthesis of Y2Ir2O7 nanoparticles via chemical solution process. Structural analysis shows single cubic phase with Fd-3m space group symmetry. The particle size and distribution were studied by Transmission Electron Microscopy experiments. The average particle size turns out to be 50nm, which is in good agreement with the XRD results. Magnetic characterization shows no evidence of long range ordering even in presence of strong correlations.

  17. Electrical transport, magnetic properties of the half-metallic Fe 3O 4-based Schottky diode

    Microsoft Academic Search

    Hong Yan; Ming Zhang; Hui Yan

    2009-01-01

    Fe3O4 thin films were prepared successfully by using the rf-sputtering technique with Fe2O3 target. The inverse spinel structure of the film was determined by X-ray diffraction (XRD) and the single phase of the Fe3O4 was confirmed by the XPS measurements. The surface roughness increases with the increase of the partial pressure of hydrogen. A high saturated magnetic field, 5000Oe, implies

  18. Effects of microstructural heterogeneity on the mechanical properties of pressed soft magnetic composite bodies

    Microsoft Academic Search

    S. Giménez; T. Lauwagie; G. Roebben; W. Heylen; O. Van der Biest

    2006-01-01

    The elastic and damping properties of two different soft magnetic composite (SMC) materials processed by a powder metallurgy route (Somaloy™500+0.5wt.% Kenolube and Somaloy™500+0.6wt.% LB1) have been characterised by means of non-destructive resonant vibration analysis, using the impulse excitation technique (IET). Microstructural characterisation by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) was carried out in order to understand

  19. Fine magnetic properties obtained in FeCo alloy nanowire arrays

    Microsoft Academic Search

    D. H. Qin; L. Cao; Q. Y. Sun; Y. Huang; H. L. Li

    2002-01-01

    Anodic aluminum oxide (AAO) was used as a template to prepare highly ordered FeCo alloy nanowire arrays. The as-deposited samples were annealed at 300, 400, 450, 500, 550 and 600 °C, respectively. The structure and magnetic properties of FeCo nanowire arrays dependence on different annealing temperature were analyzed by XRD and vibrating sample magnetometer. We found that the annealing samples

  20. Magnetic Variations

    NSDL National Science Digital Library

    Sten Odenwald

    In this activity students analyze tabulated data and convert it into a graph, search for patterns and trends, and make a prediction about future events. They discover that a graphical display of numbers may help to show patterns such as trends or varying rates of change and that such patterns sometimes can be used to make predictions about the phenomenon being graphed. This activity places the changes in Earth's magnetic field in an historical context that attemps to correct many misconceptions about Earth's magnetic field and debunk a 2003 movie that depicted dire consequences due to pole reversal.

  1. Magnetic Properties

    Microsoft Academic Search

    Joachim Wecker; Günther Bayreuther; Gunnar Ross; Roland Grössinger

    \\u000a \\u000a Magnetic materials are one of the most prominent classes of functional materials, as introduced in Sect. 1.3. They are mostly\\u000a inorganic, metallic or ceramic in nature and typically multicomponent when used in applications (e.g. alloys or intermetallic\\u000a phases). Their structure can be amorphous or crystalline with grain sizes ranging from a few nanometers (as in high-end nanocrystalline\\u000a soft magnetic materials) to centimeters

  2. Phyllosilicate-poor palagonitic dust from Mauna Kea Volcano (Hawaii): A mineralogical analogue for magnetic Martian dust?

    NASA Astrophysics Data System (ADS)

    Morris, R. V.; Graff, T. G.; Mertzman, S. A.

    2001-03-01

    The mineralogical and elemental composition of dust size fractions (<2 and <5 ?m) of eight samples of phyllosilicate-poor palagonitic tephra from the upper slopes of Mauna Kea Volcano (Hawaii) were studied by X-ray diffraction (XRD), X-ray fluorescence (XRF), visible and near-IR reflectance spectroscopy, Mössbauer spectroscopy, magnetic properties methods, and transmission electron microscopy (TEM). The palagonitic dust samples are spectral analogues of Martian bright regions at visible and near-IR wavelengths. The crystalline phases in the palagonitic dust are, in variable proportions, plagioclase feldspar, Ti-containing magnetite, minor pyroxene, and trace hematite. No basal reflections resulting from crystalline phyllosilicates were detected in XRD data. Weak, broad XRD peaks corresponding to X-ray amorphous phases (allophane, nanophase ferric oxide (possibly ferrihydrite), and, for two samples, hisingerite) were detected as oxidative alteration products of the glass; residual unaltered glass was also present. Mössbauer spectroscopy showed that the iron-bearing phases are nanophase ferric oxide, magnetite/titanomagnetite, hematite, and minor glass and ferrous silicates. Direct observation by TEM showed that the crystalline and X-ray amorphous phases observed by XRD and Mössbauer are normally present together in composite particles and not normally present as discrete single-phase particles. Ti-bearing magnetite occurs predominantly as 5-150 nm particles embedded in noncrystalline matrix material and most likely formed by crystallization from silicate liquids under conditions of rapid cooling during eruption and deposition of glassy tephra and prior to palagonitization of glass. Rare spheroidal halloysite was observed in the two samples that also had XRD evidence for hisingerite. The saturation magnetization Js and low-field magnetic susceptibility for bulk dust range from 0.19 to 0.68 Am2/kg and 3.4×10-6 to 15.5×10-6m3/kg at 293 K, respectively. Simulation of the Mars Pathfinder Magnet Array (MA) experiment was performed on Mauna Kea Volcano in areas with phyllosilicate-poor palagonitic dust and with copies of the Pathfinder MA. On the basis of the magnetic properties of dust collected by all five MA magnets and the observation that the Pathfinder MAs collected dust on the four strongest magnets, the value for the saturation magnetization of Martian dust collected in the MA experiments is revised downward from 4+/-2Am2/kg to 2.5+/-1.5Am2/kg. The revised value corresponds to 2.7+/-1.6wt% magnetite if the magnetic mineral is magnetite (using Js=92Am2/kg for pure magnetite, Fe3O4) or to 5.0+/-3.0 to 3.4+/-2.0wt% maghemite if the magnetic mineral is pure maghemite (using Js=50 to 74 Am2/kg for pure maghemite, ?-Fe2O3). Comparison of the magnetic properties of bulk Mauna Kea palagonitic dust to those for dust collected by MA magnets shows that the MA magnets extracted (culled) a subset (25-34 wt %) of composite magnetic particles from bulk dust. The extent of culling of Martian dust is not well constrained. Because the Mauna Kea palagonitic dust satisfies the essential constraints of the Pathfinder magnetic properties experiment (composite and magnetic particles capable of being collected by five MA magnets), a working hypothesis for the strongly magnetic mineral present in Martian dust and soil is magnetite (possibly Ti-bearing) formed by rapid crystallization from silicate liquids having volcanic and/or impact origins. Subsequent palagonitization of the glass produces the nanophase ferric oxide phases that dominate the spectral properties of Martian bright regions at visible and near-IR wavelengths. Magnetic and phyllosilicate-poor palagonitic dust from Mauna Kea Volcano is thus a spectral and magnetic analogue for magnetic Martian dust.

  3. Domain size correlated magnetic properties and electrical impedance of size dependent nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kamble, Ramesh B.; Varade, Vaibhav; Ramesh, K. P.; Prasad, V.

    2015-01-01

    We report here the investigations on the size dependent variation of magnetic properties of nickel ferrite nanoparticles. Nickel ferrite nanoparticles of different sizes (14 to 22 nm) were prepared by the sol-gel route at different annealing temperatures. They are characterized by TGA-DTA, XRD, SEM, TEM and Raman spectroscopy techniques for the confirmation of the temperature of phase formation, thermal stability, crystallinity, morphology and structural status of the nickel ferrite nanoparticles. The magnetization studies revealed that the saturation magnetization (Ms), retentivity (Mr) increase, while coercivity (Hc) and anisotropy (Keff) decrease as the particle size increases. The observed value of Ms is found to be relatively higher for a particle size of 22 nm. In addition, we have estimated the magnetic domain size using magnetic data and correlated to the average particle size. The calculated magnetic domain size is closely matching with the particle size estimated from XRD. Impedance spectroscopy was employed to study the samples in an equivalent circuit to understand their transport phenomena. It shows that nickel ferrite nanoparticles exhibit a non-Debye behavior with increasing particle size due to the influence of increasing disorders, surface effects, grain size and grain boundaries, etc.

  4. Exploring Magnetism: Investigating the forces of magnets

    NSDL National Science Digital Library

    This activity is a classroom and lab investigation of magnetism. Students gather results of experiments involving the forces of magnets. They use this data to develop their own experiments to test properties of magnets.

  5. Structural and magnetic characterization of electrodeposited Ni-Cu/Cu and Fe-Ni-Cu/Cu multilayer

    NASA Astrophysics Data System (ADS)

    Hedayati, Kambiz

    2015-03-01

    In this research, Ni-Cu/Cu and Fe-Ni-Cu/Cu multilayers were electrodeposited on Au/Cr/glass substrate. The XRD pattern of Ni-Cu/Cu multilayer indicates satellite peaks of Ni-Cu and Cu bilayers. The EDX results had shown that the Ni content increased with increasing magnetic layers in both Ni-Cu/Cu and Fe-Ni-Cu/Cu multilayers. The AFM images had shown that increasing the magnetic and nonmagnetic layers leads to increasing surface roughness. The VSM of samples obtained the coercivity by increasing magnetic layer thickness and by decreasing the addition of Fe to Ni-Cu/Cu multilayers.

  6. Magnetic Catalysis vs Magnetic Inhibition

    E-print Network

    Kenji Fukushima; Yoshimasa Hidaka

    2012-09-06

    We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.

  7. Magnets 2: How Strong is Your Magnet?

    NSDL National Science Digital Library

    In this lesson, students will experimentally measure the strength of a magnet and graph how the strength changes as the distance from the magnet increases, and as the barrier (masking tape) is built between the magnet and an iron object. This lesson is the second in a two-lesson series on magnets. The main concept to convey in Magnets 2: How Strong is Your Magnet? is that forces can act from a distance.

  8. Structural and magnetic characterization of as-prepared and annealed FeCoCu nanowire arrays in ordered anodic aluminum oxide templates

    SciTech Connect

    Rodríguez-González, B., E-mail: jbenito@uvigo.es [CACTI, University of Vigo, E-36310 Vigo (Spain); International Iberian Nanotechnology Laboratory, INL. Av. Mestre J. Veiga, 4715-330 Braga (Portugal); Bran, C.; Warnatz, T.; Vazquez, M. [Institute of Materials Science of Madrid, CSIC, 28049 Madrid (Spain); Rivas, J. [International Iberian Nanotechnology Laboratory, INL. Av. Mestre J. Veiga, 4715-330 Braga (Portugal)

    2014-04-07

    Herein, we report on the preparation, structure, and magnetic characterization of FeCoCu nanowire arrays grown by DC electrodeposition inside self-assembled ordered nanopores of anodic aluminum oxide templates. A systematic study of their structure has been performed both in as-prepared samples and after annealing in the temperature range up to 800?°C, although particular attention has been paid to annealing at 700?°C after which maximum magnetic hardening is achieved. The obtained nanowires have a diameter of 40?nm and their Fe{sub 0.28}Co{sub 0.67}Cu{sub 0.05} composition was confirmed by energy dispersive X-ray spectroscopy (EDS). Focused ion-beam lamellas of two samples (as-prepared and annealed at 700?°C) were prepared for their imaging in the high-resolution transmission electron microscopy (HRTEM) perpendicularly to the electron beam, where the obtained EDS compositional mappings show a homogeneous distribution of the elements. X-ray diffraction analysis, and selected area electron diffraction (SAED) patterns confirm that nanowires exhibit a bcc cubic structure (space group Im-3m). In addition, bright-dark field images show that the nanowires have a polycrystalline structure that remains essentially the same after annealing, but some modifications were observed: (i) an overall increase and sharpening of recrystallized grains, and (ii) an apparent shrinkage of the nanowires diameter. Obtained SAED patterns also show strong textured components with determined <111> and <112> crystalline directions parallel to the wires growth direction. The presence of both directions was also confirmed in the HRTEM images doing Fourier transform analyses. Magnetic measurements show strong magnetic anisotropy with magnetization easy axis parallel to the nanowires in as-prepared and annealed samples. The magnetic properties are tuned by suitable thermal treatments so that, maximum enhanced coercivity (?2.7 kOe) and normalized remanence (?0.91 Ms) values are achieved after annealing at temperature of 700?°C. The contribution of the changes in the crystalline structure, induced by the heat treatment, to the magnetic hardening of the FeCoCu nanowires is discussed.

  9. Structural and magnetic characterization of as-prepared and annealed FeCoCu nanowire arrays in ordered anodic aluminum oxide templates

    NASA Astrophysics Data System (ADS)

    Rodríguez-González, B.; Bran, C.; Warnatz, T.; Rivas, J.; Vazquez, M.

    2014-04-01

    Herein, we report on the preparation, structure, and magnetic characterization of FeCoCu nanowire arrays grown by DC electrodeposition inside self-assembled ordered nanopores of anodic aluminum oxide templates. A systematic study of their structure has been performed both in as-prepared samples and after annealing in the temperature range up to 800 °C, although particular attention has been paid to annealing at 700 °C after which maximum magnetic hardening is achieved. The obtained nanowires have a diameter of 40 nm and their Fe0.28Co0.67Cu0.05 composition was confirmed by energy dispersive X-ray spectroscopy (EDS). Focused ion-beam lamellas of two samples (as-prepared and annealed at 700 °C) were prepared for their imaging in the high-resolution transmission electron microscopy (HRTEM) perpendicularly to the electron beam, where the obtained EDS compositional mappings show a homogeneous distribution of the elements. X-ray diffraction analysis, and selected area electron diffraction (SAED) patterns confirm that nanowires exhibit a bcc cubic structure (space group Im-3m). In addition, bright-dark field images show that the nanowires have a polycrystalline structure that remains essentially the same after annealing, but some modifications were observed: (i) an overall increase and sharpening of recrystallized grains, and (ii) an apparent shrinkage of the nanowires diameter. Obtained SAED patterns also show strong textured components with determined ?111? and ?112? crystalline directions parallel to the wires growth direction. The presence of both directions was also confirmed in the HRTEM images doing Fourier transform analyses. Magnetic measurements show strong magnetic anisotropy with magnetization easy axis parallel to the nanowires in as-prepared and annealed samples. The magnetic properties are tuned by suitable thermal treatments so that, maximum enhanced coercivity (˜2.7 kOe) and normalized remanence (˜0.91 Ms) values are achieved after annealing at temperature of 700 °C. The contribution of the changes in the crystalline structure, induced by the heat treatment, to the magnetic hardening of the FeCoCu nanowires is discussed.

  10. Mapping Magnetic Influence

    NSDL National Science Digital Library

    This is an activity about mapping magnetic fields. Learners use a test magnet to create a map of the magnetic field region around a bar magnet. A Magnaprobe, or other similar test magnet, is required to do this activity. This is the third activity in the Mapping Magnetic Influence educators guide.

  11. Structural and magnetic behaviour of soft magnetic Finemet-type ribbons.

    PubMed

    Iturriza, N; Fernández, L; Chizhik, A; Vara, G; Pierna, A R; del Val, J J

    2008-06-01

    Different kinds of magnetic anisotropies have been induced during the nanocrystallization process of Co- and Ni-rich amorphous ferromagnetic (Finemet) ribbons by the application of a constant stress or an axial magnetic field during the annealing process. Magnetization measurements have evidenced the presence od macroscopic anisotropy in the treated samples. The main goal of this work has been, after a careful DSC study, the structural analysis of the treated ribbons using X-ray Diffraction and Atomic Force Microscopy (AFM), detecting substantial differences in the crystallization state and grain size of the samples depending on the thermal treatment that was carried out. Moreover, AFM measurements revealed in all the treated samples a strong nanocrystallisation of the surface without evidences of amorphous matrix, which contrast with XRD measurements that have shown a high content of amorphous phase in the bulk of the ribbons. Magneto-optical Kerr effect measurements have been performed with the aim to elucidate the complex magnetic behaviour that is expected for the surface of the ribbons, measuring surface hysteresis loops that showed much higher coercive field values than that obtained in the bulk material. PMID:18681027

  12. Synthesis of La0.6Nd0.2Na0.2MnO3 nanowire and its magnetism.

    PubMed

    Lai, S H; Wang, T F; Lan, M D

    2011-03-01

    The colossal magnetoresistance (CMR) manganite La0.6Nd0.2Na0.2MnO3 nanowires were synthesized in porous anodic alumina oxide (AAO) membrane via the sol-gel template route. X-ray diffraction (XRD) results of La0.6Nd0.2Na0.2MnO3/AAO composites verified the purity of the perovskite structure of La0.6Nd0.2Na0.2MnO3. Field emission scanning electron microscopy (FE-SEM) confirmed that the monodisperse cylindrical pores of alumina membrane were filled with manganite nanowire arrays. The nanowires were found to be essentially polycrystalline materials by high-resolution transmission electron microscope (HRTEM) images and selected electron diffraction (SAED) analysis. The Curie temperature of the La0.6Nd0.2Na0.2MnO3 nanowires determined by superconducting quantum interference device (SQUID) was much less than the the Curie temperature of the bulk material. According to our experimental results, we proposed the single domain size should be less than 50 nm conservatively. The result suggested that the finite size effect may play an important role in the reduction of the Curie temperature of the La0.6Nd0.2Na0.2MnO3 nanowires. PMID:21449351

  13. The effects of high magnetic field on the morphology and microwave electromagnetic properties of MnO{sub 2} powder

    SciTech Connect

    Jia Zhang [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China); Duan Yuping, E-mail: duanyp@dlut.edu.c [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China); Li Shuqing, E-mail: lsq6668@126.co [Beijing Aeronautical Manufacturing Technology Research Institute, 1 Jun Zhuang east Road, Chaoyang District, Beijing 100024 (China); Li Xiaogang, E-mail: lixiaogang99@263.ne [School of Materials Science and Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Liu Shunhua [Department of Materials Processing Engineering, School of Materials Science and Engineering, Dalian University of Technology, Linggong Road 2, Ganjingzi District, Dalian 116085, Liaoning Province (China)

    2010-07-15

    MnO{sub 2} with a sea urchin-like ball chain shape was first synthesized in a high magnetic field via a simple chemical process, and a mechanism for the formation of this grain shape was discussed. The as-synthesized samples were characterized by XRD, SEM, TEM, and vector network analysis. The dielectric constant and the loss tangent clearly decreased under a magnetic field. The magnetic loss tangent and the imaginary part of the magnetic permeability increased substantially. Furthermore, the theoretically calculated values of reflection loss showed that the absorption peaks shifted to a higher frequency with increases in the magnetic field strength. - Graphical abstract: MnO{sub 2} with a sea urchin-like ball chain shape is first synthesized in a high magnetic field via a simple hydrothermal route.

  14. Superconducting Magnet Division Magnet Note

    E-print Network

    Gupta, Ramesh

    . The coils are enclosed in two cryostats. The design gradient is reached at ~125 A. Details of this design design is 280 mm and the maximum operating gradient is 10 T/m. An OPERA3d model of the upper half of the proposed design is shown in Fig. 1. The complete magnet uses 24 HTS coils, each consisting of 175 turns

  15. Structural and magnetic properties of rare earth—iron–cobalt–vanadium intermetallic compounds (R: Tb, Dy)

    Microsoft Academic Search

    D Hadjiapostolidou; M Gjoka; C Sarafidis; E Pavlidou; T Bakas; O Kalogirou

    2004-01-01

    Starting with the Nd3(Fe,Ti)29 stoichiometry [Tb3(Fe1?xCox)27.4V1.6 and Dy3(Fe1?xCox)27.8V1.2; x=0.6, 0.8, 1.0] two novel series of R–Fe–Co–V intermetallic compounds with a disordered variant of the hexagonal Th2Ni17-type structure were formed. The cell parameters decrease and the Curie temperature increases with increasing Co content. XRD patterns of magnetically aligned powder samples revealed the presence of a planar magnetic anisotropy.

  16. Room Temperature Magnetism in Co-doped ZnO Nanorods

    Microsoft Academic Search

    Liguo Xu; Kai Shen; Qingyu Xu

    2011-01-01

    Zn1?x\\u000a Co\\u000a x\\u000a O (x=0, 0.02, 0.04, 0.06, 0.08, 0.10) nanorods have been synthesized by the hydrothermal method. XRD patterns show that all samples\\u000a are wurtzite structure without impurity. The magnetization measurements show that the pure ZnO is diamagnetic, while paramagnetism\\u000a dominates in Zn1?x\\u000a Co\\u000a x\\u000a O nanorods. Paramagnetism increases linearly with an increasing Co concentration. The magnetic moment calculated

  17. Magnetic and optical properties of monosized Eu-doped ZnO nanocrystals from nanoemulsion

    NASA Astrophysics Data System (ADS)

    Yoon, Hayoung; Hua Wu, Jun; Hyun Min, Ji; Sung Lee, Ji; Ju, Jae-Seon; Keun Kim, Young

    2012-04-01

    We report the synthesis and characterization of monosized Eu-doped ZnO nanocrystals via a nanoemulsion process as a function of the doping ratio. The structure, optical, and magnetic properties of the nanocrystals are investigated by XRD, TEM, PL spectrometry, and physical property measurement system. The nanocrystals as prepared show high crystallinity and tight particle size distributions with the diameters of ˜ 10 nm. The doped samples clearly exhibit the 5D0?7FJ transition emission due to the presence of the Eu3+ ions. Meanwhile, the magnetic responses demonstrate the temperature dependence and change with dopant concentration.

  18. Substituent effect in 2-benzoylmethylenequinoline difluoroborates exhibiting through-space couplings. Multinuclear magnetic resonance, X-ray diffraction, and computational study.

    PubMed

    Zakrzewska, Anna; Kolehmainen, Erkki; Valkonen, Arto; Haapaniemi, Esa; Rissanen, Kari; Ch?ci?ska, Lilianna; O?mia?owski, Borys

    2013-01-10

    The series of nine 2-benzoylmethylenequinoline difluoroborates have been synthesized and characterized by multinuclear magnetic resonance, X-ray diffraction (XRD), and computational methods. The through-space spin-spin couplings between (19)F and (1)H/(13)C nuclei have been observed in solution. The NMR chemical shifts have been correlated to the Hammett substituent constants. The crystal structures of six compounds have been solved by XRD. For two derivatives the X-ray wave function refinement was performed to evaluate the character of bonds in the NBF(2)O moiety by topological and integrated bond descriptors. PMID:23252343

  19. Time Resolved XRD Study on the Thermal Decomposition of Li1-xNi0.8Co0.15Al0.05O2 Cathode Materials for Li-ion Batteries

    SciTech Connect

    Yoon,W.; Balasubramanian, M.; Yang, X.; McBreen, J.; Hanson, J.

    2005-01-01

    Time-resolved X-ray diffraction (XRD) studies were used to monitor structural changes in charged Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathodes in the presence of electrolyte as a function of temperature. The electrolyte accelerated thermal decomposition of the charged cathode material. The presence of the electrolyte changed the paths of the structural changes and lowered the temperatures for onset of the reactions. As the degree of Li-ion deintercalation increased, the thermal decomposition took place at less elevated temperature. At low states of charge (x<0.5) the XRD pattern of Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathode heated at 450 C is similar to NiO structure. The formation of the NiO-like rock salt structure is accompanied by the formation of Li{sub 2}CO{sub 3}. In the presence of electrolyte the solvent acts as a reducing agent and also lithium extracted from the structure reacts with the solvent resulting in the formation of Li{sub 2}CO{sub 3}. Time-resolved XRD results for Li{sub 1-x}Ni{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} at higher states of charge (x>0.5), when heated from 25 to 450 C, show the conversion to a disordered spinel structure from a layered structure at elevated temperature. When subsequently heated at higher temperature, the disordered spinel structure converts to NiO-like rock salt structure.

  20. Structure and magnetic properties of highly textured nanocrystalline Mn-Zn ferrite thin film

    NASA Astrophysics Data System (ADS)

    Joseph, Jaison; Tangsali, R. B.; Pillai, V. P. Mahadevan; Choudhary, R. J.; Phase, D. M.; Ganeshan, V.

    2015-01-01

    Nanoparticles of Mn0.2Zn0.8Fe2O4 were chemically synthesized by co-precipitating the metal ions in aqueous solutions in a suitable alkaline medium. The identified XRD peaks confirm single phase spinal formation. The nanoparticle size authentication is carried out from XRD data using Debye Scherrer equation. Thin film fabricated from this nanomaterial by pulse laser deposition technique on quartz substrate was characterized using XRD and Raman spectroscopic techniques. XRD results revealed the formation of high degree of texture in the film. AFM analysis confirms nanogranular morphology and preferred directional growth. A high deposition pressure and the use of a laser plume confined to a small area for transportation of the target species created certain level of porosity in the deposited thin film. Magnetic property measurement of this highly textured nanocrystalline Mn-Zn ferrite thin film revealed enhancement in properties, which are explained on the basis of texture and surface features originated from film growth mechanism.

  1. The synthesis, molecular structure, FT-IR and XRD spectroscopic investigation of 4-[(2-{[(2-furylmethyl)imino]methyl}-4-methoxyphenoxy)methyl]benzonitrile: A comparative DFT study

    Microsoft Academic Search

    Özgür Alver; Zeliha Hayvali; Hüseyin Güler; Hakan Dal; Mustafa ?enyel

    2011-01-01

    4-[(2-{[(2-Furylmethyl)imino]methyl}-4-methoxyphenoxy)methyl]benzonitrile, a novel Schiff base compound, was prepared for the first time and its structural and vibrational properties were studied both experimentally and theoretically using FT-IR and XRD spectroscopic methods. FT-IR spectrum was recorded in the region of 4000–400cm?1. The optimized geometric structures concerning to the minimum on the potential energy surface was investigated by Becke-3-Lee–Yang–Parr (B3LYP) hybrid density functional

  2. An X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) investigation of the long-term effect on the solidification\\/stabilization (S\\/S) of arsenic(V) in Portland cement type-V

    Microsoft Academic Search

    Mohammad Y. A Mollah; Mehmet Kesmez; David L Cocke

    2004-01-01

    The long-term effects on solidification\\/stabilization (S\\/S) of As5+-bearing oxyanions (AsO3?4) in Portland cement type-V (OPC) have been investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) techniques. The results of this study confirm our previous results that the early hydration of cement is inhibited by the presence of AsO3?4, and that the inhibition is mainly caused by the

  3. Magnetic monopoles

    NASA Astrophysics Data System (ADS)

    Carrigan, R. A., Jr.; Trower, W. P.

    1983-10-01

    Theoretical and experimental investigations of the possible existence of monopoles are reviewed. The charge of monopoles was calculated by Dirac and monopoles have provided stable solutions for Yang-Mills field equations, as well as being features of grand unified theories. A dynamic induction detector possibly recorded the passage of a monopole in 1982, with data acquired being within 5 percent of theoretical predictions. Similar experiments have also been performed to find dyons, particles carrying both electric and magnetic charge. Induction, ionization, acoustical, and electromagnetic techniques are being examined for detecting monopoles. Possible sources and sinks for the particles include the Big Bang, monopolonium, galactic magnetic fields, cosmic rays, neutron stars, and accelerators, none of which are particularly productive.

  4. Tunable magnetic and magnetocaloric properties of La0.6Sr0.4MnO3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ehsani, M. H.; Kameli, P.; Ghazi, M. E.; Razavi, F. S.; Taheri, M.

    2013-12-01

    Nanoparticles of La0.6Sr0.4MnO3 with different particle sizes are synthesized by the nitrate-complex auto-ignition method. The structural and magnetic properties of the samples are investigated by X-Ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), and DC magnetization measurements. The XRD study coupled with the Rietveld refinement shows that all samples crystallize in a rhombohedral structure with the space group of R-3 C. The FT-IR spectroscopy and TEM images indicate formation of the perovskite structure with the average sizes of 20, 40, and 100 nm for the samples sintered at 700, 800, and 1100 °C, respectively. The DC magnetization measurements confirm tuning of the magnetic properties due to the particle size effects, e.g., reduction in the ferromagnetic moment and increase in the surface spin disorder by decreasing the particle size. The magnetocaloric effect (MCE) study based on isothermal magnetization vs. filed measurements in all samples reveals a relatively large MCE around the Curie temperature of the samples. The peak around the Curie temperature gradually broadens with reduction of the particle size. The data obtained show that although variations in the magnetic entropy and adiabatic temperature decrease by lowering the particle size, variation in the relative cooling power values are the same for all samples. These results make this material a proper candidate in the magnetic refrigerator application above room temperature at moderate fields.

  5. Room Temperature Magnetic Refrigerator Using Permanent Magnets

    NASA Astrophysics Data System (ADS)

    Naoki, Hirano

    2003-03-01

    This paper describes experimental results of a magnetic refrigerator which is operated at room temperature region. The feature of this study is that a permanent magnet is used to make a magnetic field. A magnetic refrigerator has been expected as an Eco-friendly refrigerator which does not use any CFCs (chlorofluorocarbons) or alternatives and as a high efficient refrigerator. But one of the technical issues for a magnetic refrigerator is that it needs a high magnetic field. A superconducting magnet has been often used to generate a high magnetic field up to about 5 T. It reduces a efficiency and increases the size of a magnetic refrigerator. In this study, a permanent magnet was adopted to generate a magnetic field of 0.6 T and confirmed the refrigeration at room temperature region with such a weak magnetic field. The magnetic refrigerator mainly consisted of two sets of FeNdB magnet with iron yokes, four sets of magnetic material vessels with driving system and cooling system of materials. Gd_1-XDyX were used as magnetic materials and they were filled in magnetic material vessels. Three kinds of materials such as Gd_1-XDyX (x = 0.11, 0.13, 0.16) were used and their Curie temperatures were 10 ^oC, 5 ^oC and 0 ^oC respectively. The magnetic material vessels were reciprocated by the driving system to apply high (0.6 T) and low (0 T) magnetic field to the materials alternatively. Each vessel had two pipes which were connected to the cooling system. The cooling system flowed alcohol doped water alternatively. The alternative magnetic field and water flow in 0.25 Hz made an active magnetic refrigeration cycle. In this configuration, the maximum temperature difference of 12 ^oC was obtained and the lowest temperature of -1 ^oC was achieved.

  6. Magnetic Field Measurements in Beam Guiding Magnets

    Microsoft Academic Search

    K. N. Henrichsen

    1998-01-01

    Electromagnets used as beam guiding elements in particle accelerators and colliders require very tight tole-rances on their magnetic fields and on their alignment along the particle path. This article describes the methods and equipment used for magnetic measurements in beam transport magnets. Descriptions are given of magnetic resonance techniques, various induction coil methods, Hall generator measurements, the fluxgate magnetometer as

  7. Patterned Magnetic Nanostructures and Quantized Magnetic Disks

    E-print Network

    Patterned Magnetic Nanostructures and Quantized Magnetic Disks STEPHEN Y. CHOU Invited Paper, opens up new opportunities for engineering innovative magnetic materials and devices, developing ultra-high-density magnetic storage, and understanding micromagnetics. This paper reviews the recent advances in patterned

  8. Thermoremanent magnetization of nonuniformly magnetized grains

    Microsoft Academic Search

    David J. Dunlop

    1998-01-01

    A simple and elegant interpretation of thermoremanent magnetization (TRM) in uniformly magnetized single-domain (SD) grains was given by Nrel 50 years ago, but the TRM acquisition processes in larger, nonuniformly magnetized grains are more varied and difficult to describe theoretically. SD TRM is a frozen high-temperature partition between two microstates: spins parallel or antiparallel to an applied magnetic field. Nonuniformly

  9. Illustrating the processability of magnetic layered double hydroxides: layer-by-layer assembly of magnetic ultrathin films.

    PubMed

    Coronado, E; Martí-Gastaldo, C; Navarro-Moratalla, E; Ribera, A; Tatay, S

    2013-05-20

    We report the preparation of single-layer layered double hydroxide (LDH) two-dimensional (2D) nanosheets by exfoliation of highly crystalline NiAl-NO3 LDH. Next, these unilamellar moieties have been incorporated layer-by-layer (LbL) into a poly(sodium 4-styrenesulfonate)/LDH nanosheet multilayer ultrathin film (UTF). Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible light (UV-vis), and X-ray diffraction (XRD) profiles have been used to follow the uniform growth of the UTF. The use of a magnetic LDH as the cationic component of the multilayered architecture enables study of the resulting magnetic properties of the UTFs. Our magnetic data show the appearance of spontaneous magnetization at ?5 K, thus confirming the effective transfer of the magnetic properties of the bulk LDH to the self-assembled film that displays glassy-like ferromagnetic behavior. The high number of bilayers accessible-more than 80-opens the door for the preparation of more-complex hybrid multifunctional materials that combine magnetism with the physical properties provided by other exfoliable layered inorganic hosts. PMID:23621644

  10. Poly-l-lysine-coated magnetic nanoparticles as intracellular actuators for neural guidance

    PubMed Central

    Riggio, Cristina; Calatayud, Maria Pilar; Hoskins, Clare; Pinkernelle, Josephine; Sanz, Beatriz; Torres, Teobaldo Enrique; Ibarra, Manuel Ricardo; Wang, Lijun; Keilhoff, Gerburg; Goya, Gerardo Fabian; Raffa, Vittoria; Cuschieri, Alfred

    2012-01-01

    Purpose It has been proposed in the literature that Fe3O4 magnetic nanoparticles (MNPs) could be exploited to enhance or accelerate nerve regeneration and to provide guidance for regenerating axons. MNPs could create mechanical tension that stimulates the growth and elongation of axons. Particles suitable for this purpose should possess (1) high saturation magnetization, (2) a negligible cytotoxic profile, and (3) a high capacity to magnetize mammalian cells. Unfortunately, the materials currently available on the market do not satisfy these criteria; therefore, this work attempts to overcome these deficiencies. Methods Magnetite particles were synthesized by an oxidative hydrolysis method and characterized based on their external morphology and size distribution (high-resolution transmission electron microscopy [HR-TEM]) as well as their colloidal (Z potential) and magnetic properties (Superconducting QUantum Interference Devices [SQUID]). Cell viability was assessed via Trypan blue dye exclusion assay, cell doubling time, and MTT cell proliferation assay and reactive oxygen species production. Particle uptake was monitored via Prussian blue staining, intracellular iron content quantification via a ferrozine-based assay, and direct visualization by dual-beam (focused ion beam/scanning electron microscopy [FIB/SEM]) analysis. Experiments were performed on human neuroblastoma SH-SY5Y cell line and primary Schwann cell cultures of the peripheral nervous system. Results This paper reports on the synthesis and characterization of polymer-coated magnetic Fe3O4 nanoparticles with an average diameter of 73 ± 6 nm that are designed as magnetic actuators for neural guidance. The cells were able to incorporate quantities of iron up to 2 pg/cell. The intracellular distribution of MNPs obtained by optical and electronic microscopy showed large structures of MNPs crossing the cell membrane into the cytoplasm, thus rendering them suitable for magnetic manipulation by external magnetic fields. Specifically, migration experiments under external magnetic fields confirmed that these MNPs can effectively actuate the cells, thus inducing measurable migration towards predefined directions more effectively than commercial nanoparticles (fluidMAG-ARA supplied by Chemicell). There were no observable toxic effects from MNPs on cell viability for working concentrations of 10 ?g/mL (EC25 of 20.8 ?g/mL, compared to 12 ?g/mL in fluidMAG-ARA). Cell proliferation assays performed with primary cell cultures of the peripheral nervous system confirmed moderate cytotoxicity (EC25 of 10.35 ?g/mL). Conclusion These results indicate that loading neural cells with the proposed MNPs is likely to be an effective strategy for promoting non-invasive neural regeneration through cell magnetic actuation. PMID:22811603

  11. Structural and magnetic effects of Cd1-xInxCr2Se4

    NASA Astrophysics Data System (ADS)

    Behera, P. Suchismita; Bhobe, P. A.; Nigam, A. K.

    2015-06-01

    Polycrystalline CdCr2Se4 spinels with non-magnetic indium substitution were investigated with an aim to study the influence of non-magnetic substitution at the Cd site on its structural and magnetic properties. We carried out powder XRD and magnetic measurements on three compositions: Cd1-xInxCr2Se4 (x=0, 0.05, 0.1). The XRD patterns were analyzed by carrying out Rietveld analysis and structural parameters were estimated. Phase purity of the compounds using reitveld refinement technique where confirming the indium distribution at tetrahedral site of the cubic close-packed sublattice formed by the selenium ions. The chemical compositions of these compounds were determined by energy dispersive x-ray analysis. Compared to parent compound, CdCr2Se4, the ferromagnetic Curie temperature TC was found to decrease from 130K to 123K and 114K as x varied from 0 to 0.05 and 0.1 respectively, whereas the saturation magnetization increases in Cd0.95In0.05Cr2Se4 and again decreases in Cd0.9In0.1Cr2Se4.

  12. Magnetic Reconnection in Astrophysical and

    E-print Network

    Magnetic Reconnection in Astrophysical and Laboratory Plasmas Ellen G. Zweibel1 and Masaaki Yamada2 astrophysics, magnetic fields, magnetic reconnection Abstract Magnetic reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma energy. Astrophysical flares, from

  13. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: Structural and optical studies by DRS, FT-IR, XRD, FESEM investigations

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-01

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400 °C and 500 °C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm-1 can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm-1 are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide.

  14. Bio-inspired green synthesis of Fe3O4 spherical magnetic nanoparticles using Syzygium cumini seed extract

    NASA Astrophysics Data System (ADS)

    Venkateswarlu, Sada; Natesh Kumar, B.; Prasad, C. H.; Venkateswarlu, P.; Jyothi, N. V. V.

    2014-09-01

    A novel and bio-inspired Fe3O4 spherical magnetic nanoparticles (SMNPs) were synthesized using Syzygium cumini (S. cumini) seed extract, which is a non-toxic ecofriendly fruit waste material. S. cumini seed extract acts as a green solvent, reducing and capping agent in which sodium acetate acts as electrostatic stabilizing agent. The green synthesized nanoparticles were characterized with the help of various techniques such as X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), Energy-dispersive spectroscopy (EDS), Vibrating sample magnetometer (VSM), FTIR spectroscopy and nitrogen adsorption and desorption analysis techniques. The XRD study divulged that the synthesized SMNPs have inverse spinel cubic structure. The hysteresis loop of Fe3O4 nanoparticles shows an excellent ferromagnetic behavior with saturation magnetization value of 13.6 emu/g.

  15. Magnetic Launcher

    NSDL National Science Digital Library

    CREAM GK-12 Program, Engineering Education Research Center, College of Engineering and Architecture,

    Students explore electromagnetism and engineering concepts using optimization techniques to design an efficient magnetic launcher. Groups start by algebraically solving the equations of motion for the velocity at the time when a projectile leaves a launcher. Then they test three different launchers, in which the number of coils used is different, measuring the range and comparing the three designs. Based on these observations, students record similarities and differences and hypothesize on the underling physics. They are introduced to Faraday's law and Lenz's law to explain the physics behind the launcher. Students brainstorm how these principals might be applied to real-world engineering problems.

  16. Magnetic Nanoparticle Sensors

    PubMed Central

    Koh, Isaac; Josephson, Lee

    2009-01-01

    Many types of biosensors employ magnetic nanoparticles (diameter = 5–300 nm) or magnetic particles (diameter = 300–5,000 nm) which have been surface functionalized to recognize specific molecular targets. Here we cover three types of biosensors that employ different biosensing principles, magnetic materials, and instrumentation. The first type consists of magnetic relaxation switch assay-sensors, which are based on the effects magnetic particles exert on water proton relaxation rates. The second type consists of magnetic particle relaxation sensors, which determine the relaxation of the magnetic moment within the magnetic particle. The third type is magnetoresistive sensors, which detect the presence of magnetic particles on the surface of electronic devices that are sensitive to changes in magnetic fields on their surface. Recent improvements in the design of magnetic nanoparticles (and magnetic particles), together with improvements in instrumentation, suggest that magnetic material-based biosensors may become widely used in the future. PMID:22408498

  17. On the surface magnetism induced atypical ferromagnetic behavior of cerium oxide (CeO2) nanoparticles

    NASA Astrophysics Data System (ADS)

    Sakara, M.; Arumugam, S.; Tripathy, S.; Balakumar, S.

    2012-06-01

    An investigation was made on the intrinsic ferromagnetic behavior of nano sized cerium oxide (ceria). The nanosized ceria was prepared by modified sol gel method with crystallite size around 7nm. Structural analysis was done by XRD which showed a single phase, impurity free fluorite type crystal structured of nano ceria. The morphological analysis by FESEM technique showed agglomerated nature of nanoparticles due to their high surface energy. The surface and bulk information was obtained from UV and visible Raman analysis. From Raman studies it was observed that the large surface defect which was the prime reason for the induced surface magnetism in the nano ceria. From magnetization studies by VSM, it was found that if magnetism was associated with the surface defects of the material. The ferromagnetic behavior of nanosized ceria is still under debate. An attempt has taken to explain the same with emphasizing the surface magnetism of ceria nanoparticles.

  18. Removal of arsenic by magnetic biochar prepared from pinewood and natural hematite.

    PubMed

    Wang, Shengsen; Gao, Bin; Zimmerman, Andrew R; Li, Yuncong; Ma, Lena; Harris, Willie G; Migliaccio, Kati W

    2014-10-28

    There is a need for the development of low-cost adsorbents to removal arsenic (As) from aqueous solutions. In this work, a magnetic biochar was synthesized by pyrolyzing a mixture of naturally-occurring hematite mineral and pinewood biomass. The resulting biochar composite was characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). In comparison to the unmodified biochar, the hematite modified biochar not only had stronger magnetic property but also showed much greater ability to remove As from aqueous solution, likely because the ?-Fe2O3 particles on the carbon surface served as sorption sites through electrostatic interactions. Because the magnetized biochar can be easily isolated and removed with external magnets, it can be used in various As contaminant removal applications. PMID:25459847

  19. Investigation of structural, thermal and magnetic properties of cadmium substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Venkata Reddy, Ch.; Byon, Chan; Narendra, B.; Baskar, D.; Srinivas, G.; Shim, Jaesool; Prabhakar Vattikuti, S. V.

    2015-06-01

    Cd substituted Cobalt ferrite nano particles are synthesis using co-precipitation method. The as prepared samples are calcinated at 300 and 600 °C respectively. The existence of single phase spinal cubic structure of the prepared ferrite material is confirmed by the powder XRD measurement. The surface morphology images, compositional features are studied by SEM with EDX, and TEM. From the FT-IR spectra the absorption bands observed at 595 and 402 cm-1 are attributed to vibrations of tetrahedral and octahedral complexes respectively. From the VSM data, parameters like magnetization, coercivity, remanent magnetization and remanent squareness are measured. The saturation magnetization value is increases with increasing calcination temperature. The DSC and TG-DTA curves reveal that the thermal stability of the prepared ferrite nanoparticles. The calcination temperature affects the crystallite size, morphology and magnetic properties of the samples.

  20. Thermal and magnetic behavior of Angustifolia Kunth bamboo fibers covered with Fe3O4 particles

    NASA Astrophysics Data System (ADS)

    Calvo, S.; Arias, N. P.; Giraldo, O.; Rosales-Rivera, A.; Moscoso, O.

    2012-08-01

    Several Angustifolia Kunth bamboo fibers, which have been previously treated with an alkaline solution, were coated with magnetite particles. The coating of the fibers was achieved by an in-situ co-precipitation method with Fe2+ and Fe3+in NaOH or NH4OH. The fibers were evaluated by chemical analysis using atomic absorption (A.A.) technique, structural characterization by X-ray diffraction (XRD), thermal stability with thermo-gravimetric analysis (TGA) in nitrogen at temperature range between 23 °C and 800 °C and magnetic behavior using vibrating sample magnetometry (VSM) applying a magnetic field between -27 KOe and 27 KOe at room temperature. We found that the thermal stability and magnetization depend of the synthesis method used to cover the Angustifolia Kunth bamboo fibers. In addition, an improved magnetic response was observed when NaOH solution is used to generate the magnetite coating on the fiber surface.

  1. Magnets: Design Guide

    NSDL National Science Digital Library

    2000-01-01

    Provided by the magnet manufacturer Total Magnet Solutions, which offers engineering assistance, stock and custom magnets, and complete magnetic sub-assemblies in prototype to production quantities, the Magnets Design Guide Web page contains a wealth of physical information. Users can read about general categories of permanent magnet functions, magnet materials and their comparisons, units of measure for magnets and their conversion factors, design considerations, finite element analysis, the B-H curve, magnet calculations, and more. A well-designed and attractive site, it provides researchers easy access to practical and informative facts and, at the very least, interesting reading.

  2. Biomimetic magnetic silk scaffolds.

    PubMed

    Samal, Sangram K; Dash, Mamoni; Shelyakova, Tatiana; Declercq, Heidi A; Uhlarz, Marc; Bañobre-López, Manuel; Dubruel, Peter; Cornelissen, Maria; Herrmannsdörfer, Thomas; Rivas, Jose; Padeletti, Giuseppina; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L; Dediu, V Alek

    2015-03-25

    Magnetic silk fibroin protein (SFP) scaffolds integrating magnetic materials and featuring magnetic gradients were prepared for potential utility in magnetic-field assisted tissue engineering. Magnetic nanoparticles (MNPs) were introduced into SFP scaffolds via dip-coating methods, resulting in magnetic SFP scaffolds with different strengths of magnetization. Magnetic SFP scaffolds showed excellent hyperthermia properties achieving temperature increases up to 8 °C in about 100 s. The scaffolds were not toxic to osteogenic cells and improved cell adhesion and proliferation. These findings suggest that tailored magnetized silk-based biomaterials can be engineered with interesting features for biomaterials and tissue-engineering applications. PMID:25734962

  3. The magnetization process: Hysteresis

    NASA Technical Reports Server (NTRS)

    Balsamel, Richard

    1990-01-01

    The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

  4. A Magnetic Personality

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students learn about magnets and how they are formed. They investigate the properties of magnets and how engineers use magnets in technology. Specifically, students learn about magnetic memory storage, which is the reading and writing of data information using magnets, such as in computer hard drives, zip disks and flash drives.

  5. Permanent magnet assembly

    DOEpatents

    Chell, Jeremy; Zimm, Carl B.

    2006-12-12

    A permanent magnet assembly is disclosed that is adapted to provide a magnetic field across an arc-shaped gap. Such a permanent magnet assembly can be used, for example, to provide a time-varying magnetic field to an annular region for use in a magnetic refrigerator.

  6. Magnetic fields in astrophysics

    Microsoft Academic Search

    Ia. B. Zeldovich; A. A. Ruzmaikin; D. D. Sokolov

    1983-01-01

    The evidence of cosmic magnetism is examined, taking into account the Zeeman effect, beats in atomic transitions, the Hanle effect, Faraday rotation, gyro-lines, and the strength and scale of magnetic fields in astrophysics. The origin of magnetic fields is considered along with dynamos, the conditions for magnetic field generation, the topology of flows, magnetic fields in stationary flows, kinematic turbulent

  7. Exploring Magnetic Field Lines

    NSDL National Science Digital Library

    NASA

    2012-06-26

    In this activity, learners explore the magnetic field of a bar magnet as an introduction to understanding Earth's magnetic field. First, learners explore and play with magnets and compasses. Then, learners trace the field lines of the magnet using the compass on a large piece of paper. This activity will also demonstrate why prominences are always "loops."

  8. Playing with Magnetism

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about magnetism and magnetic forces. Learners will explore objects to which a magnet is attracted or repelled, and investigate the attractive and repulsive forces of two like and two unlike magnetic poles. This is the first activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

  9. Magnet innovations for linacs

    SciTech Connect

    Halbach, K.

    1986-06-01

    It is possible to produce large magnetic fields at the aperture of permanent magnet quadrupoles, even when the magnetic aperture is very small. That, combined with their compactness, makes permanent magnet quadrupoles very powerful components of small aperture linacs. Results will be presented about past and present work on both fixed and variable strength permanent magnets suitable for use in and around linacs.

  10. Magnetic properties of nanocrystalline Mn1-xZnxFe2O4

    NASA Astrophysics Data System (ADS)

    V, Jagadeesha Angadi.; Rudraswamy, B.; Matteppanavar, Shidaling; Bharathi, P.; Praveena, K.

    2015-06-01

    Nanocrystalline Mn1-xZnxFe2O4 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) were prepared via solution combustion method. Structural and morphology of Mn-Zn ferrites were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Magnetic properties were carried out using vibrating sample magnetometer (VSM) at room temperature (RT) up to maximum field of 1.5 T. The room temperature real and imaginary part of permeability (?' and ??) has been measured in the frequency range of 1MHz to 1GHz. The room temperature XRD patterns exhibits the spinel cubic (Fm-3m) structure and broad XRD patterns shows the presence of nanoparticles. The imaginary part of the permeability (??) gradually increased with the frequency and took a broad maximum at a certain frequency, where the real permeability (?') rapidly decreases, which is known as natural resonance. The coercive filed values are low, hence probability of domain rotation is also lower and the magnetization decreased with zinc substitution. The values of ?' and ?? increases sharply, attained a maximum and then decreases with zinc content.

  11. Glass Forming Ability of Hard Magnetic Nd55Al20Fe25 Bulk Glassy Alloy with Distinct Glass Transition

    Microsoft Academic Search

    L. Xia; C. L. Jo; Y. D. Dong

    2005-01-01

    Nd55Al20Fe25 bulk sample was prepared in the shape of rods 3 mm in diameter by suction casting. The sample exhibits typical amorphous characters in XRD pattern, distinct glass transition in DSC traces and hard magnetic properties. The distinct glass transition, which is invisible in DSC traces of previously reported Nd---Al---Fe ternary BMGs, allows us to investigate the glass forming ability

  12. Study of Phase Separation in Na 2O–B 2O 3 Glass System by Nuclear Magnetic Resonance

    Microsoft Academic Search

    Wei-Fang Du; Koji Kuraoka; Tomoko Akai; Tetsuo Yazawa

    2000-01-01

    The 11B nuclear magnetic resonance (NMR) spectra, together with X-ray diffraction (XRD) and scanning electron microscopy (SEM), have been used to investigate the phase separation in 15Na2O–85B2O3 binary glass. Based on the present investigation we suggest that the phase equilibrium in sodium borate glasses is controlled by the rate competition of the nucleation and crystal growth between two immiscible phases

  13. Synthesis and magnetic properties of cobalt ferrite (CoFe 2O 4) nanoparticles prepared by wet chemical route

    Microsoft Academic Search

    K. Maaz; Arif Mumtaz; S. K. Hasanain; Abdullah Ceylan

    2007-01-01

    Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single-phase cobalt ferrite nanoparticles in the range 15–48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature

  14. Nanostructure, magnetic and optical properties of Co-doped ZnO films prepared by a wet chemical method

    Microsoft Academic Search

    Aihua Wang; Binglin Zhang; Xinchang Wang; Ning Yao; Zhifeng Gao; Yukun Ma; Lan Zhang; Huizhong Ma

    2008-01-01

    Co-doped ZnO films with nanorod structures are fabricated by a simple wet chemical method combined with an electrodeposition process on the ITO substrates. This method is proved to be a repeatable, low-cost and high-yield route to synthesize Co-doped ZnO magnetical nanocrystals. SEM measurements show the nanorod structure. X-ray diffraction (XRD) spectra demonstrate that the nanorods are ZnO crystals with (1

  15. Structural features and magnetic property of nano-sized transition metal dispersed carbons from naphthalene by pressure

    Microsoft Academic Search

    Xiaohong Chen; Huaihe Song

    2007-01-01

    The transition metal nanoparticle dispersed carbon materials were synthesized by co-carbonization of naphthalene with transition\\u000a metal compounds, i.e., ferrocene, cobalt acetate and nickel acetate at 540 °C for 6 h under autogenous pressure. The morphologies,\\u000a structural features and magnetic properties of these metal\\/carbon nanomaterials were compared by means of SEM, TEM, XRD and\\u000a VSM measurements. It was found that, coalescent spherulites with

  16. Magnetic properties of hexagonal strontium ferrite thick film synthesized by sol–gel processing using SrM nanoparticles

    Microsoft Academic Search

    Ali Ghasemi; Akimitsu Morisako; Xiaoxi Liu

    2008-01-01

    Strontium ferrite SrFe12O19 (SrM) thick films have been synthesized using a spinning coating sol–gel process. The coating sol was formed from SrFe12O19 powders dispersed in the strontium ferrite raw sol. XRD, TEM, SEM, vibrating sample magnetometer (VSM) and ac susceptometer were employed to evaluate the structure, composition and magnetic properties of SrFe12O19 thick films. The results indicated that a uniform

  17. Diluted magnetic semiconductor properties in Zn 1?x Cu x O nanoparticles synthesized by sol gel route

    Microsoft Academic Search

    R. Elilarassi; P. Sambasiva Rao; G. Chandrasekaran

    2011-01-01

    Nanoparticles of ZnO:Cu Diluted Magnetic Semiconductor (DMS) are prepared using sol gel method. The structural, optical and\\u000a EPR properties of them are investigated. The XRD patterns of them show the formation of polycrystalline and hexagonal wurtzite\\u000a structure without any secondary phase formation. The average size of particles ranges from 14 to 19 nm. In the optical absorption\\u000a study of the samples,

  18. ZnO based diluted magnetic semiconductor thin films by RF magnetron sputtering for spin photonic devices

    Microsoft Academic Search

    J. Elanchezhiyan; K. P. Bhuvana; N. Gopalakrishnan; T. Balasubramanian

    2007-01-01

    Transition metal (TM) doped ZnO is a promising diluted magnetic semiconductor (DMS) material for the fabrication of spintronics devices. In this paper, we have investigated Mn and Cr doped ZnO thin films grown by RF magnetron sputtering. The films grown on Si(100) and sapphire (Al2O3) have been characterized by X-ray diffraction (XRD) and Vibrating Sample Magnetometer (VSM) to know its

  19. Superconducting magnet

    DOEpatents

    Satti, John A. (Naperville, IL)

    1980-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  20. Synthesis and characterization of magnetic palygorskite nanoparticles and their application on methylene blue remotion from water

    NASA Astrophysics Data System (ADS)

    Middea, Antonieta; Spinelli, Luciana S.; Souza, Fernando G.; Neumann, Reiner; Gomes, Otavio da F. M.; Fernandes, Thais L. A. P.; de Lima, Luiz C.; Barthem, Vitoria M. T. S.; de Carvalho, Fernanda V.

    2015-08-01

    Recently there has been considerable interest in magnetic sorbents materials, which is added excellent capabilities such as sorption and magnetic response to an applied field. Accordingly, palygorskite nanoparticles were covered by magnetite using a co-precipitation technique and characterized by: X-ray fluorescence (XRF), X-ray diffraction (XRD), surface analysing and scanning electron microscopy (SEM) with element analysis and mapping, particle size, pore surface area (BET), density, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and zeta potential. Additionally, magnetic properties were studied by SQUID magnetometer, magnetic force microscopy (MFM) and also using a simple experimental setup. Magnetic nanoparticles produced had average diameters in a nanometric range. The amount of iron present in the nanoparticles increased by six times after the magnetization and a superparamagnetic behavior was exhibited with high saturation magnetization, from 4.0 × 10-4 Am2/kg to about 20 Am2/kg. A weight loss was also observed around 277 °C-339 °C by TGA, indicating a structural change from magnetite to maghemite, which confirms the magnetization of palygorskite. Batch adsorption experiments were carried out for the removal of methylene blue cationic dye from aqueous solution using pure and covered by magnetite palygorskite nanoparticles as adsorbents. Furthermore, about 90% of methylene blue was removed within 3 min using magnetized palygorskite.

  1. Pharmacologically significant complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) of novel Schiff base ligand, (E)-N-(furan-2-yl methylene) quinolin-8-amine: Synthesis, spectral, XRD, SEM, antimicrobial, antioxidant and in vitro cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Shakir, M.; Hanif, Summaiya; Sherwani, Mohd. Asif; Mohammad, Owais; Al-Resayes, Saud I.

    2015-07-01

    A novel series of metal complexes of the types, [ML2(H2O)2]Cl2 and [ML2]Cl2 [M = Mn(II), 1; Co(II), 2; Ni(II), 3; Cu(II), 4; and Zn(II), 5] were synthesized by the interaction of ligand, L (E)-N-(furan-2-yl methylene) quinolin-8-amine, derived from the condensation of 2-furaldehyde and 8-aminoquinoline. The synthesized ligand and its metal complexes were characterized on the basis of results obtained from elemental analysis, ESI-MS, XRD, SEM, TGA/DTA, FT-IR, UV-Vis, magnetic moment and 1H and 13C NMR spectroscopic studies. EPR parameters were recorded in case of complex 4. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics and antioxidant activity against standard control at variable concentrations revealed that the metal complexes show enhanced antimicrobial and free radical scavenging activities in general as compared to free ligand. However, the complexes 1 and 5 have shown best antioxidant activity among all the metal complexes. Furthermore, comparative in-vitro antiproliferative activity on ligand and its metal chelates performed on MDA-MB-231 (breast carcinoma), KCL22 (blood lymphoid carcinoma), HeLa (cervical carcinoma) cell lines and normal cells (PBMC) revealed that metal chelates show moderate to good activity as compared to ligand where as complex 1 seems to be the most promising one possessing a broad spectrum of activity against all the selected cancer cell lines with IC50 < 2.10 ?M.

  2. Optimization of magnetic powdered activated carbon for aqueous Hg(II) removal and magnetic recovery.

    PubMed

    Faulconer, Emily K; von Reitzenstein, Natalia V Hoogesteijn; Mazyck, David W

    2012-01-15

    Activated carbon is known to adsorb aqueous Hg(II). MPAC (magnetic powdered activated carbon) has the potential to remove aqueous Hg to less than 0.2 ?g/L while being magnetically recoverable. Magnetic recapture allows simple sorbent separation from the waste stream while an isolated waste potentially allows for mercury recycling. MPAC Hg-removal performance is verified by mercury mass balance, calculated by quantifying adsorbed, volatilized, and residual aqueous mercury. The batch reactor contained a sealed mercury-carbon contact chamber with mixing and constant N(2) (g) headspace flow to an oxidizing trap. Mercury adsorption was performed using spiked ultrapure water (100 ?g/L Hg). Mercury concentrations were obtained using EPA method 245.1 and cold vapor atomic absorption spectroscopy. MPAC synthesis was optimized for Hg removal and sorbent recovery according to the variables: C:Fe, thermal oxidation temperature and time. The 3:1 C:Fe preserved most of the original sorbent surface area. As indicated by XRD patterns, thermal oxidation reduced the amorphous characteristic of the iron oxides but did not improve sorbent recovery and damaged porosity at higher oxidation temperatures. Therefore, the optimal synthesis variables, 3:1 C:Fe mass ratio without thermal oxidation, which can achieve 92.5% (± 8.3%) sorbent recovery and 96.3% (± 9%) Hg removal. The mass balance has been closed to within approximately ± 15%. PMID:22104766

  3. Structural and magnetic properties of Sr2FeMoO6 film prepared by electrophoresis technique

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Xu, Z. F.; Liang, J.; Pei, J.; Sun, H. B.

    2014-03-01

    Double perovskite Sr2FeMoO6 film was fabricated by electrophoresis method on single crystal Si substrate. The post-annealing treatment was carried out at 900 °C, 960 °C, 1060 °C and 1100 °C with 5% H2/Ar atmosphere. Surface micrograph, structural and magnetic properties of the film have been investigated. It is found that the annealing temperature plays an important role on the phase formation and magnetic properties. According to X-ray diffraction (XRD), single phase Sr2FeMoO6 film was obtained at annealing temperature 1100 °C, the film shows typical polycrystal property. However, the superstructure reflection assigning the ordering arrangement of Fe and Mo atoms in the perovskite structure disappears in our XRD pattern. Raman detection finds two peaks at around 440 cm-1 and 620 cm-1, which belongs to Sr2FeMoO6 phase. Consistent with XRD results, typical impurity like SrMoO4 appears at around 880 cm-1 in the film annealed at lower temperature. Microstructure investigation shows that the surface of the film is homogeneous and the grain size of particles increases with annealing temperature. Temperature dependence of magnetization reveal that the highest Curie temperature (TC=282 K) is obtained from the film annealed at 1100 °C. Owing to the large amount of anti-site defect, the highest TC is still lower than that of parent Sr2FeMoO6 powder.

  4. Heteropolyhedral silver compounds containing the polydentate ligand N,N,O-E-[6-(hydroxyimino)ethyl]-1,3,7-trimethyllumazine. Preparation, spectral and XRD structural study and AIM calculations.

    PubMed

    Jiménez-Pulido, Sonia B; Hueso-Ureña, Francisco; Fernández-Liencres, M Paz; Fernández-Gómez, Manuel; Moreno-Carretero, Miguel N

    2013-01-14

    The oxime derived from 6-acetyl-1,3,7-trimethyllumazine (1) ((E-6-(hydroxyimino)ethyl)-1,3,7-trimethylpteridine-2,4(1H,3H)-dione, DLMAceMox) has been prepared and its molecular and crystal structure determined from spectral and XRD data. The oxime ligand was reacted with silver nitrate, perchlorate, thiocyanate, trifluoromethylsulfonate and tetrafluoroborate to give complexes with formulas [Ag(2)(DLMAceMox)(2)(NO(3))(2)](n) (2), [Ag(2)(DLMAceMox)(2)(ClO(4))(2)](n) (3), [Ag(2)(DLMAceMox)(2)(SCN)(2)] (4), [Ag(2)(DLMAceMox)(2)(CF(3)SO(3))(2)(CH(3)CH(2)OH)]·CH(3)CH(2)OH (5) and [Ag(DLMAceMox)(2)]BF(4) (6). Single-crystal XRD studies show that the asymmetrical residual unit of complexes 2, 3 and 5 contains two quite different but connected silver centers (Ag1-Ag2, 2.9-3.2 Å). In addition to this, the Ag1 ion displays coordination with the N5 and O4 atoms from both lumazine moieties and a ligand (nitrato, perchlorato or ethanol) bridging to another disilver unit. The Ag2 ion is coordinated to the N61 oxime nitrogens, a monodentate and a (O,O)-bridging nitrato/perchlorato or two monodentate O-trifluoromethylsulfonato anions. The coordination polyhedra can be best described as a strongly distorted octahedron (around Ag1) and a square-based pyramid (around Ag2). The Ag-N and Ag-O bond lengths range between 2.22-2.41 and 2.40-2.67 Å, respectively. Although the structure of 4 cannot be resolved by XRD, it is likely to be similar to those described for 2, 3 and 5, containing Ag-Ag units with S-thiocyanato terminal ligands. Finally, the structure of the tetrafluoroborate compound 6 is mononuclear with a strongly distorted tetrahedral AgN(4) core (Ag-N, 2.27-2.43 Å). Always, the different Ag-N distances found clearly point to the more basic character of the oxime N61 nitrogen atom when compared with the pyrazine N5 one. A topological analysis of the electron density within the framework provided by the quantum theory of atoms in molecules (QTAIM) using DFT(M06L) levels of theory has been performed. Every Ag-Ag and Ag-ligand interaction has been characterized in terms of Laplacian of the electron density, [nabla](2)?(r), and the total energy density, H(r). PMID:23085985

  5. Magnetism of Carbonados

    NASA Technical Reports Server (NTRS)

    Kletetschka, G.; Taylor, P. T.; Wasilewski, P. J.

    2000-01-01

    Origin of Carbonado is not clear. Magnetism of Carbonado comes from the surface, indicating contemporary formation of both the surface and magnetic carriers. The interior of carbonado is relatively free of magnetic phases.

  6. Structural and magnetic properties of Co{sub 2}Ti{sub 1?x}Fe{sub x}Al (0 ? x ? 0.5) alloys

    SciTech Connect

    Pal, Lakhan, E-mail: lakhanbainsla@gmail.com; Gupta, Sachin, E-mail: lakhanbainsla@gmail.com; Suresh, K. G., E-mail: lakhanbainsla@gmail.com [Department of Physics, Indian Institute of Technology Bombay, Mumbai-400076 (India)

    2014-04-24

    In this work we studied the effect of partial Fe substitution for Ti on the structural and magnetic properties of the Co{sub 2}TiAl. X-ray diffraction analysis indicates the presence of B2 type disorder for x > 0, (111) reflections are absent for x > 0 which is the characteristic of B2 type disorder. XRD analysis also shows presence of second phase. Magnetization measurements also confirm the presence of dual phase. Curie temperature of the alloys increases with increase in Fe concentration. Saturation magnetic moments agree very well with those calculated by Slater-Pauling rule.

  7. What are Magnetic Fields?

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about magnetic fields. Using iron filings, learners will observe magnets in various arrangements to investigate the magnetic field lines of force. This information is then related to magnetic loops on the Sun's surface and the magnetic field of the Earth. This is the second activity in the Magnetic Math booklet; this booklet can be found on the Space Math@NASA website.

  8. Model a Magnet

    NSDL National Science Digital Library

    2012-08-03

    This is a summative activity about magnets. Learners will observe a demonstration of the action of a magnet on a test tube of iron filings, answer questions, and, using the concepts learned in previous activities, write an essay about their understanding of the demonstration. This is the fourth activity in the Mapping Magnetic Influence educators guide. Learners should complete the other three activities in that guide (Seeing Magnetism, What Do You Know about Magnets, and Magnet Map) prior to beginning this activity.

  9. Visualizing Magnetic Field Lines

    NSDL National Science Digital Library

    2014-09-18

    In this activity, students take the age old concept of etch-a-sketch a step further. Using iron filings, students begin visualizing magnetic field lines. To do so, students use a compass to read the direction of the magnet's magnetic field. Then, students observe the behavior of iron filings near that magnet as they rotate the filings about the magnet. Finally, students study the behavior of iron filings suspended in mineral oil which displays the magnetic field in three dimensions.

  10. High Temperature, Permanent Magnet Biased Magnetic Bearings 

    E-print Network

    Gandhi, Varun R.

    2010-07-14

    The Electron Energy Corporation (EEC) along with the National Aeronautics and Space Administration (NASA) is researching magnetic bearings. The purpose of this research was to design and develop a high-temperature (1000?F) magnetic bearing system...

  11. Laced permanent magnet quadrupole drift tube magnets

    SciTech Connect

    Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

    1989-03-01

    Twenty-three laced permanent magnet quadrupole drift tube magnets have been constructed, tested, and installed in the SuperHILAC heavy ion linear accelerator at LBL, marking the first accelerator use of this new type of quadrupole. The magnets consist of conventional tape-wound quadrupole electromagnets, using iron pole-pieces, with permanent magnet material (samarium cobalt) inserted between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the individual quadrupole magnets in a drift tube linac is never reversed, we can take advantage of this asymmetrical saturation to provide about 20% greater focusing strength than is available with conventional quadrupoles, while replacing the vanadium permendur poletips with iron poletips. Comparisons between these magnets and conventional tape-wound quadrupoles will be presented. 3 refs., 5 figs.

  12. Magnetization of ferromagnetic clusters

    SciTech Connect

    Onishi, Naoki [Univ. of Tokyo (Japan). Inst. of Physics; Bertsch, G. [Univ. of Washington, Seattle, WA (United States); Yabana, Kazuhiro [Niigata Univ. (Japan). Dept. of Physics

    1995-02-01

    The magnetization and deflection profiles of magnetic clusters in a Stern-Gerlach magnet are calculated for conditions under which the magnetic moment is fixed in the intrinsic frame of the cluster, and the clusters enter the magnetic field adiabatically. The predicted magnetization is monotonic in the Langevin parameter, the ratio of magnetic energy {mu}{sub 0}B to thermal energy k{sub B}T. In low field the average magnetization is 2/3 of the Langevin function. The high-field moment approaches saturation asymptotically as B{sup {minus}1/2} instead of the B{sup {minus}1} dependence in the Langevin function.

  13. The Third Flight Magnet

    NASA Technical Reports Server (NTRS)

    McGhee, R. Wayne

    1998-01-01

    A self-shielded superconducting magnet was designed for the NASA Goddard Space Flight Center Adiabatic Demagnetization Refrigerator Program. This is the third magnet built from this design. The magnets utilize Cryomagnetics' patented ultra-low current technology. The magnetic system is capable of reaching a central field of two tesla at slightly under two amperes and has a total inductance of 1068 henries. This final report details the requirements of the magnet, the specifications of the resulting magnet, the test procedures and test result data for the third magnet (Serial # C-654-M), and recommended precautions for use of the magnet.

  14. Magnetic Fields Matter

    NSDL National Science Digital Library

    2014-09-18

    This lesson introduces students to the effects of magnetic fields in matter addressing permanent magnets, diamagnetism, paramagnetism, ferromagnetism, and magnetization. First students must compare the magnetic field of a solenoid to the magnetic field of a permanent magnet. Students then learn the response of diamagnetic, paramagnetic, and ferromagnetic material to a magnetic field. Now aware of the mechanism causing a solid to respond to a field, students learn how to measure the response by looking at the net magnetic moment per unit volume of the material.

  15. Exploring Magnetic Fields

    NSDL National Science Digital Library

    In this activity, students investigate the presence of magnetic fields around magnets, the sun and the earth. They will explore magnetic field lines, understand that magnetic lines of force show the strength and direction of magnetic fields, determine how field lines interact between attracting and repelling magnetic poles, and discover that the earth and sun have magnetic properties. They will also discover that magnetic force is invisible and that a "field of force" is a region or space in which one object can attract or repel another.

  16. Electrical, dielectric and magnetic characterization of Bi-Cr substituted M-type strontium hexaferrite nanomaterials

    NASA Astrophysics Data System (ADS)

    Shakoor, Sajeela; Ashiq, Muhammad Naeem; Malana, Muhammad Aslam; Mahmood, Azhar; Warsi, Muhammad Farooq; Najam-ul-Haq, Muhammad; Karamat, Nazia

    2014-08-01

    Strontium hexaferrite nanoparticles substituted with bismuth and chromium having nominal composition SrFe12-2xBixCrxO19 (x=0.2, 0.4, 0.6, 0.8) have been synthesized by the sol-gel method. The samples are characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), DC electrical resistivity, magnetic and dielectric measurements. The XRD data shows that the nanoparticles are crystallized into single hexagonal magnetoplumbite phase. Room temperature DC electrical resistivity decreases on increasing the Bi-Cr contents. The dielectric constant, dielectric loss and tangent loss decrease with the frequency. The magnetic properties such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) increase with increasing the dopant concentration up to x=0.2 and then decrease with further increase in dopant content. Coercivity decreases with increasing the dopant content up to x=0.2 then increases with further increase in dopant content. The increase in Ms and Mr while decrease in Hc indicates that the material with composition SrBi0.2Cr0.2Fe11.6O19 is suitable for magnetic recording media.

  17. Magnetic properties of Nd-Ga-Fe{sub bal}-Nb-B alloy

    SciTech Connect

    Kim, Hyunkyu; Sung Kim, Chul, E-mail: cskim@kookmin.ac.kr [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of); Yong An, Sung; Ryong Choi, Kang; Choi, Moonhee [Corporate R and D, Samsung Electro-Mechanics, Suwon (Korea, Republic of)

    2014-05-07

    Here, we have synthesized Nd-Ga-Fe{sub bal}-Nb-B alloy by strip casting method. The crystalline and magnetic properties of sample were investigated with x-ray diffractometer (XRD), vibrating sample magnetometer (VSM), and Mössbauer spectrometer. The XRD pattern was analyzed with the Rietveld refinement method, indicating a tetragonal structure and the space group of P4{sub 2}/mnm. The temperature dependence of zero-field cooled (ZFC) magnetization curve was measured under applied field at temperature ranging from 4.2 to 740?K. From the ZFC curve, Curie temperature and spin reorientation temperature are determined to be 615?K and 130?K, respectively. Also, Mössbauer spectra were measured at various temperatures ranging from 4.2 to 620?K. Each spectrum was fitted with 6-sextets for Fe site (8j{sub 1}, 8j{sub 2}, 16k{sub 1}, 16k{sub 2}, 4c, and 4e), and magnetic hyperfine field, Isomer shift, electric quadrupole shift, and area ratio values were obtained from the fit. We observed the change in slope of magnetic hyperfine field and electric quadrupole shift at 130?K while the Curie temperature was determined to be 615?K from the measurement of zero velocity counter, agreeing with the values obtained from VSM measurements.

  18. Influence of complexing agent on the electrodeposited Co Pt W magnetic thin films

    NASA Astrophysics Data System (ADS)

    Wei, Guoying; Ge, Hongliang; Huang, Lihong; Wu, Qiong; Wang, Xinqing; Huang, Liming

    2008-03-01

    Complexing agents are often used to improve the quality of electrodeposited alloys. Influence of different complexing agents with hydroxycarboxylic acid group on the electrodeposited Co-Pt-W thin films has been investigated. Cathodic polarization curves show that the polarization behaviors of electroplating bath with different complexing agents are very different. Surface morphology, phase composition and magnetic properties are observed by means of FESEM, XRD and vibrating sample magnetometer (VSM), respectively. It has been found out that, if citrate was used as complexing agent, the Co-Pt-W thin films were homogeneous and the granular crystals with the average grain size of 2 ?m have been observed. Co-Pt-W thin films exhibited hexagonal close packed (hcp) lattice and strong perpendicular anisotropic magnetic behavior ( Hc? = 215.5 kA/m; Hc? = 55.4 kA/m). In the presence of gluconate, needle-like deposits were obtained and a strong face centered cubic (fcc(1 1 1)) texture was measured. The Co-Pt-W thin films showed isotropic magnetic behavior. In the case of tartate and malate, the coexistence of needle-like deposits and cellular deposits appeared. The XRD patterns showed that the mixed fcc and hcp phase formed. Perpendicular anisotropic magnetic behaviors of thin films, from malate or tartate baths, were not obvious.

  19. Magnetic phase evolution and particle size estimation study on nanocrystalline Mg-Mn ferrites

    NASA Astrophysics Data System (ADS)

    Modi, K. B.; Vasoya, N. H.; Lakhani, V. K.; Pathak, T. K.

    2015-01-01

    The nanocrystalline spinel ferrite compositions of Mg x Mn1- x Fe2O4 ( x = 0.0, 0.2, 0.4 and 0.5) system have been synthesized by the chemical co-precipitation route. The structural and magnetic properties have been studied by means of X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and Mossbauer spectroscopic measurements. 57Fe Mossbauer spectra of three specimens, as prepared, annealed at 200 °C and sintered at 1,100 °C, of the studied compositions are recorded and analyzed to study the magnetic phase evolution. The Mossbauer spectra of as-prepared samples show a paramagnetic doublet, annealed samples exhibit simultaneous presence of a central paramagnetic doublet superimposed on two broad magnetic sextets while spectra for sintered samples show two well-resolved Zeeman split sextets corresponding to the Fe3+ ions at the tetrahedral sites and the other due to the Fe3+ ions at the octahedral sites of the spinel lattice along with presence of central doublet. The particle size estimated from the probability versus hyperfine magnetic field distribution curve is in agreement with those determine from XRD and TEM analysis, validates the method employed.

  20. Synthesis and Characterization of Co-doped ZnO Dilute Magnetic Semiconducting Nanorods

    NASA Astrophysics Data System (ADS)

    Das, N.; Khanra, S.; Bhamidipati, S.; Manivannan, K.; Kahol, P.; Ghosh, K.

    2012-02-01

    Transition-metal doped ZnO dilute magnetic semiconducting nanomaterials are considered as ideal systems for carrying out research in the field of spintronics as they can successfully combine magnetism and electronics in a single substance. ZnO is a wurtzite-type wide-bandgap semiconductor of the II-VI semiconductor group with band gap energy of 3.37 eV. Hydrothermal synthesis of undoped ZnO and Co-doped ZnO nanorods is carried out using aqueous solutions of Zn(NO3)2.6H2O, Co(C2H3OO)2.4 H2O, and using NH4OH as hydrolytic catalyst. Nanomaterials of different sizes and shapes were synthesized by varying the process parameters such as molarity (0.15M, 0.3M, 0.5M) and pH (8-11) of the precursors, growth temperature (130^oC), and annealing time during the hydrothermal Process. Structural, morphological, optical and magnetic properties are studied using various techniques such as XRD, SEM, UV-vis spectroscopy, and SQUID magnetometer. XRD and SEM studies reveal nanorods with hexagonal wurtzite structure with length in the range of 200 to 500 nm, and cross section in the range of 30 to 60 nm. Detailed structural, optical, and magnetic properties will be discussed in this presentation.

  1. Conservation of Moroccan manuscript papers aged 150, 200 and 800 years. Analysis by infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS).

    PubMed

    Hajji, Latifa; Boukir, Abdellatif; Assouik, Jamal; Lakhiari, Hamid; Kerbal, Abdelali; Doumenq, Pierre; Mille, Gilbert; De Carvalho, Maria Luisa

    2015-02-01

    The preservation of manuscripts and archive materials is a serious problem for librarians and restorers. Paper manuscript is subjected to numerous degradation factors affecting their conservation state. This research represents an attempt to evaluate the conservation restoration process applied in Moroccan libraries, especially the alkaline treatment for strengthening weakened paper. In this study, we focused on six samples of degraded and restored paper taken from three different Moroccan manuscripts aged 150, 200 and 800 years. In addition, the Japanese paper used in restoration has been characterized. A modern paper was also analyzed as reference. A three-step analytical methodology based on infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS) analysis was developed before and after restoration in order to determine the effect of the consolidation treatment on the paper structure. The results obtained by XRD and ATR-FTIR disclosed the presence of barium sulfate (BaSO4) in all restored paper manuscripts. The presence of calcium carbonate (CaCO3) in all considered samples was confirmed by FTIR spectroscopy. The application of de-acidification treatment causes significant changes connected with the increase of intensity mostly in the region 1426 cm(-1), assigned to the asymmetric and symmetric CO stretching mode of calcite, indicating the effectiveness of de-acidification procedure proved by the rise of the alkaline reserve content allowing the long term preservation of paper. Observations performed by SEM magnify the typical paper morphology and the structure of fibbers, highlighting the effect of the restoration process, manifested by the reduction of impurities. PMID:25459630

  2. Studies the alterations of biochemical and mineral contents in bone tissue of mus musculus due to aluminum toxicity and the protective action of desferrioxamine and deferiprone by FTIR, ICP-OES, SEM and XRD techniques.

    PubMed

    Sivakumar, S; Khatiwada, Chandra Prasad; Sivasubramanian, J

    2014-05-21

    The present study has attempt to analyze the changes in the biochemical and mineral contents of aluminum intoxicated bone and determine the protective action of desferrioxamine (DFO) and deferiprone (DFP) by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), and scanning electron microscopy (SEM) techniques for four groups of animals such as control (Group I), aluminum intoxicated (Group II), Al+DFP (Group III) and Al+DFO+DFP (Group IV) treated groups respectively. The FTIR spectra of the aluminum intoxicated bone showed significant alteration in the biochemical constituents. The bands ratio at I1400/I877 significantly decreased from control to aluminum, but enhanced it by Al+DFP to Al+DFO+DFP treated bone tissue for treatments of 16 weeks. This result suggests that DFO and DFP are the carbonate inhibitor, recovered from chronic growth of bone diseases and pathologies. The alteration of proteins profile indicated by Amide I and Amide II, where peak area values decreased from control to aluminum respectively, but enhanced by treated with DFP (p.o.) and DFO+DFP (i.p.) respectively. The XRD analysis showed a decrease in crystallinity due to aluminum toxicity. Further, the Ca, Mg, and P contents of the aluminum exposed bone were less than those of the control group, and enhanced by treatments with DFO and DFP. The concentrations of trace elements were found by ICP-OES. Therefore, present study suggests that due to aluminum toxicity severe loss of bone minerals, decrease in the biochemical constituents and changes in the surface morphology. PMID:24583473

  3. One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages

    PubMed Central

    2009-01-01

    Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca.100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (?-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures. PMID:20596278

  4. FULL PAPERS XRD and electrochemical investigation of

    E-print Network

    Boyer, Edmond

    .E. Timoshenko,[b] A.V.Guterman,[b] I.N. Zakharchenko,[b] G.P. Petin[b] , B.Dkhil[a} Pt-Co/C electrocatalysts nanoparticles. The latter two phenomena are especially intrinsic to the oxygen electrode. They reduce, (iv) formation of a thin Pt shell at the surface of the nanoparticles due to selective dissolution

  5. Effect of silver addition on structural, electrical and magnetic properties of Fe3O4 thin films prepared by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Master, Ridhi; Choudhary, R. J.; Phase, D. M.

    2012-04-01

    The structural, electrical, and magnetic properties of Agx-(Fe3O4)1-x (x = 0, 0.02, 0.10) composite films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), resistivity as well as magnetization measurements. The samples used in the present work were prepared by the pulsed laser deposition (PLD) technique on a single crystal Si (111) substrate. XRD spectra reveal that Ag added samples show polycrystalline growth on the Si substrate in distinction to oriented growth of Fe3O4 on a similar substrate. XRD and XPS data confirm that silver is present in metallic form. Temperature dependent resistivity data corresponding to all the three samples show a characteristic Verway transition (Tv) around 121 K. However, the resistivity pattern of the Ag added sample with x = 0.10 shows the tunneling behavior below Tv, which is attributed to the accumulation of silver clusters across the boundary of Fe3O4 grains. Both Ag added (x = 0.02, 0.10) Fe3O4 films show positive magnetoresistance which is in contrast to negative magnetoresistance observed in pure Fe3O4 at room temperature. Magnetization measurements reveal that Ag granules reduce the saturation magnetization of Fe3O4.

  6. Synthesis of cobalt ferrite (CoFe2O4) nanoparticles using combustion, coprecipitation, and precipitation methods: A comparison study of size, structural, and magnetic properties

    NASA Astrophysics Data System (ADS)

    Houshiar, Mahboubeh; Zebhi, Fatemeh; Razi, Zahra Jafari; Alidoust, Ali; Askari, Zohreh

    2014-12-01

    In this work the cobalt ferrite (CoFe2O4) nanoparticles are synthesized using three different methods; combustion, coprecipitation, and precipitation. Size, structural, and magnetic properties were determined and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). XRD data analysis showed an average size of 69.5 nm for combustion, 49.5 nm for coprecipitation, and 34.7 nm for precipitation samples which concorded with SEM images. XRD data further revealed a reverse cubic spinel structure with the space group Fd-3m in all three samples. VSM data of samples showed a saturation point in the magnetic field of less than 15 kOe. Magnetization saturation (Ms) was 56.7 emu/g for combustion synthestized samples, 55.8 emu/g for coprecipitation samples, and 47.2 emu/g for precipitation samples. Coercivity (Hc) was 2002 Oe for combustion synthestized samples, 850 Oe for coprecipitation samples, and 233 Oe for precipitation samples. These results show that various methods of nanoparticle synthesis can lead to different particle sizes and magnetic properties. Hc and Ms are greatest in the combustion method and least in precipitation method.

  7. Reflectivity (visible and near IR), Moessbauer, static magnetic, and X ray diffraction properties of aluminum-substituted hematites

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Schulze, Darrell G.; Lauer, Howard V., Jr.; Agresti, David G.; Shelfer, Tad D.

    1992-01-01

    The effect of substituting iron by aluminum in polymorphs of Fe2O3 and FeOOH on their reflectivity characteristics was investigated by comparing data on visible and NIR reflectivities and on static magnetic, XRD, and Moessbauer properties for a family of aluminum-substituted hematites alpha-(Fe,Al)2O3, with compositions where the values of the Al/(Al+Fe) ratio were up to 0.61. Samples were prepared by oxidation of magnetite, dehydroxylation of goethite, and direct precipitation. The analytical methods used for obtaining diffuse reflectivity spectra (350-2200 nm), Moessbauer spectra, and static magnetic data are those described by Morris et al. (1989).

  8. Magnetic properties of Fe doped SmCrO{sub 3} perovskite

    SciTech Connect

    Bakshi, Venugopal Rao; Devarasetty, Suresh Babu, E-mail: s-devarasetty1956@yahoo.co.uk [Department of Physics, Osmania University, Hyderabad-500007 (India); Prasad, Bandi Vittal [Department of Physics, Nizam College (Osmania University), Hyderabad-500007 (India); Gade, Narsinga Rao; Chou, C F [Centre for Condensed Matter Physics, National Taiwan University, Taipei, Taiwan (China)

    2014-04-24

    The compound SmCr{sub 1?x} Fe{sub x}O{sub 3} perovskites were prepared by citric acid route. the samples were characterized by XRD and SEM. The temperature and field dependent magnetization measurements were carried out in the temperature range of 5K ?400 K at 0.01T field and ?5T to 5T field at 2K. SmCrO3 compound has shown two magnetic transition temperatures at 197 K and 38 K. The observed behavior at 197 K is the characteristic of anti-ferromagnetic ordering of Cr{sup 3+} moments with weak ferromagnetism. The drop in magnetization below 38 K is due to the spin reorientation of Sm{sup 3+} in anti ferromagnetic arrangement and Cr{sup 3+}spins. the doping of Fe in SmCrO{sub 3} compound has shown a decrease in T{sub N1} and also the two magnetization reversals at 177K and 57K. The magnetic behavior at low temperatures is (Tmagnetization reversals offers the characteristic switching of magnetization without changing the direction of the applied magnetic field.

  9. Laced permanent magnet quadrupole drift tube magnets

    SciTech Connect

    Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

    1988-10-01

    A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs.

  10. Contactless Magnetic Slip Ring

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroyuki (Inventor); Deardon, Joe D. (Inventor)

    1997-01-01

    A contactless magnetic slip ring is disclosed having a primary coil and a secondary coil. The primary and secondary coils are preferably magnetically coupled together, in a highly reliable efficient manner, by a magnetic layered core. One of the secondary and primary coils is rotatable and the contactless magnetic slip ring provides a substantially constant output.

  11. Spiral Magnets as Magnetoelectrics

    Microsoft Academic Search

    T. Kimura

    2007-01-01

    Magnetoelectric multiferroics is an old but emerging class of materials that combine coupled electric and magnetic dipole order. In these materials, ferroelectric and magnetic (ferromagnetic or antiferromagnetic) states coexist or compete with each other. The interaction leads to a so-called magnetoelectric effect, which is the induction of magnetization by an electric field or electric polarization by a magnetic field. In

  12. Magnetic Membrane System

    DOEpatents

    McElfresh, Michael W.; (Livermore, CA); Lucas, Matthew S.; (Pasadena, CA)

    2004-12-30

    The present invention provides a membrane with magnetic particles. In one embodiment the membrane is created by mixing particles in a non-magnetic base. The membrane may act as an actuator, a sensor, a pump, a valve, or other device. A magnet is operatively connected to the membrane. The magnet acts on and changes the shape of the membrane.

  13. Electric and magnetic fields

    Microsoft Academic Search

    K. B. Maracas

    1994-01-01

    Increasing electrification brings increased human exposures to electric and magnetic fields, commonly called EMFs, and growing evidence suggests that exposure to even low frequency, low energy, electric and magnetic fields may be related to adverse health effects. This paper focuses on magnetic fields and strategies that address them. The challenges faced by scientists in understanding magnetic field interactions with humans,

  14. Electricity and Magnetism

    NSDL National Science Digital Library

    In this two-part activity, students learn about electromagnetism by constructing electromagnets and observing their behavior. They will discover that there is a close relationship between electricity and magnetism in that moving magnets can induce electric currents and that electric currents can cause magnetism. They also learn that electric current flowing in a wire creates a magnetic field around it.

  15. Magnetic crust of Mars

    Microsoft Academic Search

    Jafar Arkani-Hamed

    2005-01-01

    The strong magnetic anomalies of Mars require highly magnetic sources in the crust. The bottom of the potentially magnetic layer is constrained by the Curie temperature of its magnetic carriers, and the top of the layer is constrained by the thickness of the uppermost crust that has been demagnetized by the impacts. This paper presents a systematic study of the

  16. Magnetic pulse welding technology

    Microsoft Academic Search

    Ahmad K. Jassim

    2010-01-01

    In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the

  17. Magnetic Imaging Wolfgang Kuch

    E-print Network

    Kuch, Wolfgang

    Magnetic Imaging Wolfgang Kuch Freie Universit¨at Berlin, Institut f¨ur Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany kuch@physik.fu-berlin.de Abstract. Imaging of magnetic domains has- ern techniques is used nowadays routinely for magnetic imaging of magnetic ma- terials

  18. Magnetic fields of galaxies

    Microsoft Academic Search

    Aleksandr A. Ruzmaikin; Dmitrii D. Sokolov; Anvar M. Shukurov

    1988-01-01

    The current state of the understanding of the magnetic fields of galaxies is reviewed. A simple model of the turbulent dynamo is developed which explains the main observational features of the global magnetic fields of spiral galaxies. The generation of small-scale chaotic magnetic fields in the interstellar medium is also examined. Attention is also given to the role of magnetic

  19. A tunable magnetic inductor

    Microsoft Academic Search

    N. Ning; X. P. Li; J. Fan; W. C. Ng; Y. P. Xu; X. Qian; H. L. Seet

    2006-01-01

    For integrated radio-frequency applications, tunable magnetic inductors are expected. A tunable magnetic inductor, based on magnetoimpedance effect, is presented in this paper. The proposed inductor is constructed with a magnetic inductor body, wound by an insulated coil, inducing a longitudinal dc bias magnetic field when a dc control current is flowing through. Formed by a conductive core coated by a

  20. Influence of size/crystallinity effects on the cation ordering and magnetism of ?-lithium ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Jovi?, N.; Prekajski, M.; Kremenovi?, A.; Jan?ar, B.; Kahlenberg, V.; Anti?, B.

    2012-02-01

    ?-lithium ferrite (Li0.5Fe2.5O4) nanoparticles have been prepared using two synthesis routes: citrate gel decomposition as well as the Pechini method. Analysis of HRTEM images of the particles showed that they have a core/shell structure, an average size of ˜10 nm and stacking faults parallel to the (110) planes. In both samples, the distribution of the Li and Fe cations was found to be partially ordered on the octahedral sites (Wyckoff positions 4b and 12d of space group P4332). According to literature data, Li0.5Fe2.5O4 should adopt a disordered spinel structure (so called ?-phase, space group Fd3¯m) for crystallites of 10 nm or less in size. In this study it is shown that (a) the symmetry of the Li0.5Fe2.5O4 nanoparticles depends on the degree of their crystallinity and (b) the ordered crystal structures can be formed even for crystallites of 5-6 nm in size. By fitting the room temperature Mössbauer spectra it was obtained that the hyperfine field values are lower in the sample synthesized by the Pechini method. The Pechini process probably resulted in larger distortions of the cation environments than the citrate gel decomposition method. The saturation magnetization in turn was higher for the material obtained by the gel decomposition approach.

  1. Functionalization of electrospun magnetically separable TiO 2 -coated SrFe 12 O 19 nanofibers: strongly effective photocatalyst and magnetic separation

    Microsoft Academic Search

    Cong-Ju Li; Jiao-Na Wang; Xiu-Yan Li; Lian-Lian Zhang

    2011-01-01

    Magnetically separable TiO2-coated SrFe12O19 electrospun nanofibers were obtained successfully by means of sol–gel, electrospinning, and coating technology, followed\\u000a by heat treatment at 550–650 °C for 3 h. The average diameter of the electrospun fibers was 500–600 nm. The fibers were characterized\\u000a by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and vibrating sample\\u000a magnetometer (VSM). The optimized calcining temperature was

  2. Mapping Magnetic Field Lines

    NSDL National Science Digital Library

    This is a lesson about the magnetic field of a bar magnet. The lesson begins with an introductory discussion with learners about magnetism to draw out any misconceptions that may be in their minds. Then, learners freely experiment with bar magnets and various materials, such as paper clips, rulers, copper or aluminum wire, and pencils, to discover that magnets attract metals containing iron, nickel, and/or cobalt but not most other materials. Next, learners experiment with using a magnetic compass to discover how it is affected by the magnet and then draw the magnetic field lines of the magnet by putting dots at the location of the compass arrow. This is the first lesson in the first session of the Exploring Magnetism teacher guide.

  3. Dimensionality dependent magnetic and magnetocaloric response of La0.6Ca0.4MnO3 manganite.

    PubMed

    Anwar, M S; Ahmed, Faheem; Koo, Bon Heun

    2014-11-01

    We report the sol-gel synthesis and impact of reduced dimensionality on the magnetocaloric properties of La0.6Ca0.4MnO3 manganite. The synthesized powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and magnetization measurements. The XRD results indicated that the La0.6Ca0.4MnO3 nanoparticles have single phase nature with orthorhombic structure. FE-SEM results suggested that the nanoparticles are agglomerated and crystallite size increases with the annealing temperature. Magnetization measurements show that the La0.6Ca0.4MnO3 nanoparticles exhibit transition temperature (T(c)) below room temperature. The transition temperature was found to increase with the increasing the crystallite size. Maximum in magnetic entropy change, (?S(M))(max) shows interesting behaviour and was found to vary with the particle size. At magnetic field of 1 T, the value of (?S(M))(max) - 0.13 J/kg K was observed at 213 K for the sample annealed at 600 degrees C. Also, the increment in the value of (?S(M))(max) was observed at higher annealing temperature. This study shows that the magnetic entropy of pervoskite manganite can be tuned by tuning the crystallite size of the manganites. PMID:25958596

  4. Magnetically operated check valve

    NASA Technical Reports Server (NTRS)

    Morris, Brian G. (inventor); Bozeman, Richard J., Jr. (inventor)

    1994-01-01

    A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

  5. High efficiency magnetic bearings

    NASA Technical Reports Server (NTRS)

    Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

    1993-01-01

    Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

  6. Facility Measures Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Honess, Shawn B.; Narvaez, Pablo; Mcauley, James M.

    1991-01-01

    Partly automated facility measures and computes steady near magnetic field produced by object. Designed to determine magnetic fields of equipment to be installed on spacecraft including sensitive magnetometers, with view toward application of compensating fields to reduce interfernece with spacecraft-magnetometer readings. Because of its convenient operating features and sensitivity of its measurements, facility serves as prototype for similar facilities devoted to magnetic characterization of medical equipment, magnets for high-energy particle accelerators, and magnetic materials.

  7. The Magnetic Field

    NSDL National Science Digital Library

    Jeffrey Barker

    This demonstration of the magnetic field lines of Earth uses a bar magnet, iron filings, and a compass. The site explains how to measure the magnetic field of the Earth by measuring the direction a compass points from various points on the surface. There is also an explanation of why the north magnetic pole on Earth is actually, by definition, the south pole of a magnet.

  8. Electricity and Magnetic Fields

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    The grand challenge for this legacy cycle unit is for students to design a way to help a recycler separate aluminum from steel scrap metal. In previous lessons, they have looked at how magnetism might be utilized. In this lesson, students think about how they might use magnets and how they might confront the problem of turning the magnetic field off. Through the accompanying activity students explore the nature of an electrically induced magnetic field and its applicability to the needed magnet.

  9. Drawing Magnetic Fields

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    Students use a compass and a permanent magnet to trace the magnetic field lines produced by the magnet. By positioning the compass in enough spots around the magnet, the overall magnet field will be evident from the collection of arrows representing the direction of the compass needle. In activities 3 and 4 of this unit, students will use this information to design a way to solve the grand challenge of separating metal for a recycling company.

  10. What is Magnetism?

    NSDL National Science Digital Library

    2012-08-03

    This is an activity about magnetism and magnetic forces. Learners will explore objects to which a magnet is attracted or repelled and record information in a learning log. Additionally, learners will identify magnetic devices or phenomena they encounter at home, at school, in nature, and in other locales. This is the first activity in the Magnetic Math booklet; this booklet can be found on the Space Math@NASA website.

  11. Exploring Magnetism on Earth

    NSDL National Science Digital Library

    2005-01-01

    This teacher's guide contains four lessons that provide a way for teachers to introduce students to and elaborate on Earth's changing magnetic field. It covers learning to navigate using Earth's magnetic field and compass, Earth's magnetic pole and its motion across Earth's surface, magnetic reversals on Earth, and Earth's currently declining magnetic field. These lessons have been taught primarily in math, geology, and astronomy classes.

  12. Heteropolar Magnetic Suspension

    NASA Technical Reports Server (NTRS)

    Misovec, Kathleen; Johnson, Bruce; Downer, James; Eisenhaure, David; Hockney, Richard

    1990-01-01

    Compact permanent-magnet/electromagnet actuator has six degrees of freedom. Heteropolar magnetic actuator conceived for use as actively controlled vibration-isolating suspension device. Exerts forces along, and torques about, all three principal coordinate axes to resist all three components of translational vibration and all three components of rotational vibration. Inner cylinder suspended magnetically within outer cylinder. Electro-magnet coils interact with fields of permanent magnets to provide active control of suspending force and torque.

  13. Structural, dielectric and magnetic properties of Ni substituted zinc ferrite

    NASA Astrophysics Data System (ADS)

    Kumbhar, S. S.; Mahadik, M. A.; Mohite, V. S.; Rajpure, K. Y.; Kim, J. H.; Moholkar, A. V.; Bhosale, C. H.

    2014-08-01

    NixZn1-xFe2O4 ferrite has been synthesized by the ceramic method using Ni CO3, ZnO, Fe2O3 precursors. The influence of Ni content on the structural, morphological, electrical and magnetic properties of NixZn1-xFe2O4 ferrites is studied. The X-ray diffraction (XRD) analysis reveals that the samples are polycrystalline with spinel cubic structure. The SEM images of NixZn1-xFe2O4 ferrite show that the grain size decreases with an increase in the Ni content. The tetrahedral and octahedral vibrations in the samples are studied by IR spectra. Frequency dependence of dielectric constant shows dielectric dispersion due to the Maxwell-Wagner type of interfacial polarization. Conduction mechanism due to polarons has been analyzed by measuring the AC conductivity. Impedance spectroscopy is used to study the electrical behavior. Magnetic properties of NixZn1-xFe2O4 are studied by using hysteresis loop measurement. The maximum value of saturation magnetization of 132.8 emu/g obtained for the composition, x=0.8, is attributed to magnetic moment of Fe3+ ions.

  14. Microwave Dielectric and Magnetic Properties of Co-Zn Ferrites

    NASA Astrophysics Data System (ADS)

    Lamani, A. R.; Jayanna, H. S.; Naveen, C. S.; Rajeeva, M. P.; Prasanna, G. D.

    2015-02-01

    The dielectric permittivity, loss tangent, in the frequency range 1MHz to 1.8 GHz and hysteresis loop parameters at room temperature were studied on a series of Zn substituted cobalt ferrites with general formula Co1-xZnx Fe2O4 where (x=0.0, 0.2, 0.4, 0.6, 1.0.). The experimental results indicate that the Zn substitution affects all these parameters. The observed dispersion in dielectric permittivity with frequency is in accordance with Maxwell-Wagner model. The high temperature sintering is used to synthesize these materials via solid state reaction route and these samples were characterized by X-ray diffractometer (XRD), vibrating sample magnetometer (VSM). The saturation magnetizations (MS) Hc and Mr of the Particles were measured at room temperature. Here for the smaller dopent concentration Ms increases with increasing in the Zn content this can explained on the basis of increased number of magnetic ions in the spinel lattice, at some point Ms decrease because of the difference between the magnetic moment of Fe2+ and Zn2+, the magnetic moment of the A sub lattice will increases and the moment of the B sub lattice will decrease. The variation of crystalline shape ellipsoid is correlated with variation of dielectric constant.

  15. Magnetic nanoparticle motion in external magnetic field

    NASA Astrophysics Data System (ADS)

    Usov, N. A.; Liubimov, B. Ya

    2015-07-01

    A set of equations describing the motion of a free magnetic nanoparticle in an external magnetic field in a vacuum, or in a medium with negligibly small friction forces is postulated. The conservation of the total particle momentum, i.e. the sum of the mechanical and the total spin momentum of the nanoparticle is taken into account explicitly. It is shown that for the motion of a nanoparticle in uniform magnetic field there are three different modes of precession of the unit magnetization vector and the director that is parallel the particle easy anisotropy axis. These modes differ significantly in the precession frequency. For the high-frequency mode the director points approximately along the external magnetic field, whereas the frequency and the characteristic relaxation time of the precession of the unit magnetization vector are close to the corresponding values for conventional ferromagnetic resonance. On the other hand, for the low-frequency modes the unit magnetization vector and the director are nearly parallel and rotate in unison around the external magnetic field. The characteristic relaxation time for the low-frequency modes is remarkably long. This means that in a rare assembly of magnetic nanoparticles there is a possibility of additional resonant absorption of the energy of alternating magnetic field at a frequency that is much smaller compared to conventional ferromagnetic resonance frequency. The scattering of a beam of magnetic nanoparticles in a vacuum in a non-uniform external magnetic field is also considered taking into account the precession of the unit magnetization vector and director.

  16. Magnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Wu, Mitchell B. (inventor); Harwell, William D. (inventor)

    1988-01-01

    A magnetic attachment mechanism adapted for interfacing with the manipulator arm of a remote manipulator system and comprising a pair of permanent magnets of rare earth material are arranged in a stator-rotor relationship. The rotor magnet is journalled for rotation about its longitudinal axis between pole plates of the stator magnet, each of which includes an adhering surface. In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet is closely adjacent to a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces for attracting a ferrous magnetic plate, or the like, affixed to the payload. When the rotor magnet is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet is disposed closely adjacent to a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces, which permits the release of a payload. An actuator for selectively rotating the rotor magnet between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For affecting an optimal rigidized attachment the payload is provided with guide means cooperable with guide means on the housing of the mechanism for directing adhering surfaces of the polar plates to the ferrous plate.

  17. Janus nanobelts: fabrication, structure and enhanced magnetic-fluorescent bifunctional performance

    NASA Astrophysics Data System (ADS)

    Ma, Qianli; Yu, Wensheng; Dong, Xiangting; Wang, Jinxian; Liu, Guixia

    2014-02-01

    A new nanostructure of magnetic-fluorescent bifunctional Janus nanobelts with Fe3O4/PMMA as one half and Tb(BA)3phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe3O4/PMMA]//[Tb(BA)3phen/PMMA] magnetic-fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special nanostructure. Compared with Fe3O4/Tb(BA)3phen/PMMA composite nanobelts, the magnetic-fluorescent bifunctional Janus nanobelts provided better performance. The new magnetic-fluorescent bifunctional Janus nanobelts have potential applications in novel nano-bio-label materials, drug target delivery materials and future nanodevices due to their excellent magnetic-fluorescent properties, flexibility and insolubility. Moreover, the construction technique for the Janus nanobelts is of universal significance for the fabrication of other multifunctional Janus nanobelts.A new nanostructure of magnetic-fluorescent bifunctional Janus nanobelts with Fe3O4/PMMA as one half and Tb(BA)3phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe3O4/PMMA]//[Tb(BA)3phen/PMMA] magnetic-fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special nanostructure. Compared with Fe3O4/Tb(BA)3phen/PMMA composite nanobelts, the magnetic-fluorescent bifunctional Janus nanobelts provided better performance. The new magnetic-fluorescent bifunctional Janus nanobelts have potential applications in novel nano-bio-label materials, drug target delivery materials and future nanodevices due to their excellent magnetic-fluorescent properties, flexibility and insolubility. Moreover, the construction technique for the Janus nanobelts is of universal significance for the fabrication of other multifunctional Janus nanobelts. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05472a

  18. Facile one-step solvothermal synthesis of iron oxide/polypyrrole nanocomposites and their magnetic properties.

    PubMed

    Wang, Hong; Lai, Xiaoyong

    2013-02-01

    Iron oxide/polypyrrole (PPy) nanocomposites (NCs) were prepared by a facile one-step solvothermal process using FeCl3 x 6H2O and pyrrole as starting materials. The resultant products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and superconducting quantum interference device magnetometer (SQUID). TEM image suggested the mesoporosity of the iron oxide/polypyrrole nanocomposites and pyrrole is found to play an important role in controlling the final morphology and porosity of the products. Magnetic hysteresis measurement reveals that nanocomposite shows a superparamagnetic behavior, and possesses a larger saturation magnetization strength (M(s)) of about 15.06 emu/g at room temperature, which allows its application in adsorption or separation as magnetically recyclable materials. PMID:23646672

  19. Biosynthesis and magnetic properties of mesoporous Fe 3O 4 composites

    NASA Astrophysics Data System (ADS)

    Zhou, Weijia; He, Wen; Zhong, Shide; Wang, Yingjun; Zhao, Hongshi; Li, Zhengmao; Yan, Shunpu

    2009-04-01

    Magnetic Fe 3O 4 materials with mesoporous structure are synthesized by co-precipitation method using yeast cells as a template. The X-ray diffraction (XRD) pattern indicates that the as-synthesized mesoporous hybrid Fe 3O 4 is well crystallized. The Barrett-Joyner-Halenda (BJH) models reveal the existence of mesostructure in the dried sample which has a specific surface area of 96.31 m 2/g and a pore size distribution of 8-14 nm. Transmission electron microscopy (TEM) measurements confirm the wormhole-like structure of the resulting samples. The composition and chemical bonds of the Fe 3O 4/cells composites are studied by Fourier transform infrared (FT-IR) spectroscopy. Preliminary magnetic properties of the mesoporous hybrid Fe 3O 4 are characterized by a vibrating sample magnetometer (VSM). The magnetic Fe 3O 4/cells composites with mesoporous structure have potential applications in biomedical areas, such as drug delivery.

  20. Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid.

    PubMed

    Ismail, Raid A; Sulaiman, Ghassan M; Abdulrahman, Safa A; Marzoog, Thorria R

    2015-08-01

    In this study, (50-110nm) magnetic iron oxide (?-Fe2O3) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV-VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. PMID:26042717

  1. Structural and magnetic properties of MgFe2O4 ceramic

    NASA Astrophysics Data System (ADS)

    Manikandan, M.; Manimuthu, P.; Venkateswaran, C.

    2014-01-01

    Magnesium ferrite (MgFe2O4) is one of the important and versatile spinel ferrite (usually written as (Mg1-xFex)[MgxFe2-x]O4) having low saturation magnetization value, high resistivity and reproducible characteristics. The stoichiometric phase of MgFe2O4 was successfully prepared by ball milling assisted sintering process. XRD pattern of the sample shows the formation of stoichiometric MgFe2O4 phase. The HRSEM image shows a distribution of particle size. Vibrating Sample Magnetometer study at room temperature shows a hysteresis loop behavior with a low saturation magnetization of about 20 emu/g and a small coercivity value. The temperature versus magnetization curve shows the ferromagnetic to paramagnetic transition.

  2. Magnetic, dielectric and sensing properties of manganese substituted copper ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, E. Ranjith; Jayaprakash, R.; Devi, G. Sarala; Reddy, P. Siva Prasada

    2014-04-01

    Manganese substituted copper ferrite nanoparticles were synthesized by an auto-combustion technique using metal nitrates and urea for gas sensor application. The products were characterized by XRD, SEM, EDX, TEM and VSM techniques. The effect of annealing temperature on the particle size, magnetic and dielectric properties of Mn-Cu ferrite nanoparticles was analyzed. The size of the particles are in the range of ~9-45 nm. The effect of annealing on the magnetic properties is discussed with the help of variation in saturation magnetization (Ms) and coercivity (Hc) by vibrating sample magnetometer (VSM). The dielectric loss and dielectric constant have been measured in the frequency range of 100 kHz-5 MHz. Furthermore, Conductance response of Mn-Cu ferrite nanomaterial was measured by exposing the material to reducing gas like liquefied petroleum gas (LPG).

  3. Magnetism and spin dynamics of novel encapsulated iron oxide superparamagnetic nanoparticles.

    PubMed

    Arosio, Paolo; Baldi, Giovanni; Chiellini, Federica; Corti, Maurizio; Dessy, Alberto; Galinetto, Pietro; Gazzarri, Matteo; Grandi, Marco Simone; Innocenti, Claudia; Lascialfari, Alessandro; Lorenzi, Giada; Orsini, Francesco; Piras, Anna Maria; Ravagli, Costanza; Sangregorio, Claudio

    2013-07-28

    Encapsulated Fe3O4 nanoparticles of average diameters d = 12 nm are obtained by coprecipitation, in the presence of 2-methoxyethanol hemiester of poly(maleic anhydride-alt-butyl vinyl ether) 5% grafted with poly(ethylene glycol) (VP-MAG nanoparticles). A complete characterization of nude and encapsulated nanoparticles through structural techniques (namely XRD, TEM, SEM), Raman spectroscopy and magnetic measurements has been performed. These nanoparticles compared with commercial compounds (ENDOREM®) present superparamagnetic behavior and nuclear relaxivities that make them promising as magnetic resonance imaging (MRI) contrast agents (CAs). We found that our nanostructures exhibit r2 relaxivity higher than those of commercial CAs over the whole frequency range. The MRI efficiency of our samples was related to their microstructural and magnetic properties. PMID:23736525

  4. In situ XRD Studies of Li-ion Cells with Mixed LiMn2O4 and LiCo1/3Ni1/3Mn1/3O2 Composite Cathode

    SciTech Connect

    Nam, K.; Yoon, W; Shin, H; Chung, K; Choi, S; Yang, X

    2009-01-01

    The structural changes of the composite cathode made by mixing spinel LiMn2O4 and layered LiNi1/3Co1/3Mn1/3O2 in 1:1 wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to {approx}5.2 V vs. Li/Li+, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the LiNi1/3Co1/3Mn1/3O2 component only. When the cell voltage reaches at {approx}4.0 V vs. Li/Li+, lithium extraction from the spinel LiMn2O4 component starts and becomes the major contributor for the cell capacity due to the higher rate capability of LiMn2O4. When the voltage passed 4.3 V, the major structural changes are from the LiNi1/3Co1/3Mn1/3O2 component, while the LiMn2O4 component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5 V and 4.2 V, the structural changes are dominated by the spinel LiMn2O4 component, with much less changes in the layered LiNi1/3Co1/3Mn1/3O2 component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research.

  5. Structural Changes and Thermal Stability of Charged LiNix Mny CozO2 Cathode Materials Studied by Combined In Situ Time-Resolved XRD and Mass Spectroscopy

    DOE PAGESBeta

    Bak, Seong-Min; Hu, Enyuan; Zhou, Yongning; Yu, Xiqian; Senanayake, Sanjaya D.; Cho, Sung-Jin; Kim, Kwang-Bum; Chung, Kyung Yoon; Yang, Xiao-Qing; Nam, Kyung-Wan

    2014-12-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time- resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygenmore »release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3?-m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3-m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. This systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.« less

  6. Reaction of H{sub 2} and H{sub 2}S with CoMoO{sub 4} and NiMoO{sub 4}: TPR, XANES, time-resolved XRD, and molecular-orbital studies

    SciTech Connect

    Rodriguez, J.A.; Chaturvedi, S.; Hanson, J.C. [Brookhaven National Lab., Upton, NY (United States). Dept. of Chemistry] [Brookhaven National Lab., Upton, NY (United States). Dept. of Chemistry; Brito, J.L. [Inst. Venezolano de Investigaciones Cientificas, Caracas (Venezuela). Centro de Quimica] [Inst. Venezolano de Investigaciones Cientificas, Caracas (Venezuela). Centro de Quimica

    1999-02-04

    The combination of two metals in an oxide matrix can produce materials with novel physical and chemical properties. The reactivity of a series of cobalt and nickel molybdates ({alpha}-AMoO{sub 4}, {beta}-AMoO{sub 4}, and AmoO{sub 4}{center_dot}nH{sub 2}O; A = Co or Ni) toward H{sub 2} and H{sub 2}S was examined using temperature programmed reduction (TPR), synchrotron-based X-ray powder diffraction (XRD), and X-ray absorption near-edge-spectroscopy (XANES). In general, the cobalt and nickel molybdates are more reactive toward H{sub 2} and easier to reduce than pure molybdenum oxides: MoO{sub 2} < MoO{sub 3} < CoMoO{sub 4} < NiMoO{sub 4}. The interaction of H{sub 2} with surfaces of {alpha}-NiMoO{sub 4}, {alpha}-CoMoO{sub 4}, and {alpha}-MoO{sub 3} was investigated using ab initio SCF calculations and cluster models. The mixed-metal oxides are easier to reduce due to the combination of two factors. First, it is easier to adsorb and dissociate H{sub 2} on Ni or Co sites than on Mo sites of an oxide. And second, as a result of differences in the strength of the metal-oxygen bonds, it is easier to remove oxygen as water from the nickel and cobalt molybdates than from MoO{sub 3} or MoO{sub 2}. The extra reactivity that the Co and Ni atoms provide also makes the rate of sulfidation of the cobalt and nickel molybdates faster than that of pure molybdenum oxides. For the adsorption of H{sub 2}S, HS, and S on {alpha}-NiMoO{sub 4} and {alpha}-MoO{sub 3} clusters, the results of ab initio SCF calculations show bigger bonding energies on the Ni sites than on the Mo sites. In these systems, the oxidation state of the Ni atoms is substantially lower (i.e., larger electron density) than that of the Mo atoms, favoring the formation of Ni {r_arrow} SH and Ni {r_arrow} S dative bonds. Results of time-resolved XRD and XANES indicate that the reduced AMoO{sub 4} compounds can be regenerated by reaction with O{sub 2} at high temperatures (350--450 C). A similar procedure (S{sub a} + O{sub 2,gas} {r_arrow} SO{sub 2,gas}) can be used to remove most of the sulfur from the sulfided oxides.

  7. Structural Changes and Thermal Stability of Charged LiNix Mny CozO2 Cathode Materials Studied by Combined In Situ Time-Resolved XRD and Mass Spectroscopy

    DOE PAGESBeta

    Bak, Seong-Min [Brookhaven National Lab. (BNL), Upton, NY (United States); Hu, Enyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhou, Yongning [Brookhaven National Lab. (BNL), Upton, NY (United States); Yu, Xiqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cho, Sung-Jin [Johnson Control Advanced Power Solution, Milwaukee, WI (United States); North Carolina A&T Univ., Greensboro, NC (United States). Joint School of Nano Science and Nano Engineering; Kim, Kwang-Bum [Yonsei Univ., Seoul, (Korea, Republic of). Dept of Material Science and Engineering; Chung, Kyung Yoon [Korea Inst. of Science and Technology (KIST), Seoul (Korea, Republic of); Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States); Nam, Kyung-Wan [Dongguk Univ., Seoul (Korea, Republic of); Dept. of Energy and Materials Engineering

    2014-12-24

    Thermal stability of charged LiNixMnyCozO2 (NMC, with x + y + z = 1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time- resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability, comparable to the low-nickel-content materials (e.g., NMC333 and NMC433), while having a high capacity close to the high-nickel-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co, and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of a layered structure (R3?-m) but Co ions prefer to migrate to the 8a tetrahedral sites of a spinel structure (Fd3-m) during the thermal decomposition. Such element-dependent cation migration plays a very important role in the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of nickel content to manganese and cobalt contents. This systematic study provides insight into the rational design of NMC-based cathode materials with a desired balance between thermal stability and high energy density.

  8. Structural changes and thermal stability of charged LiNixMnyCozO? cathode materials studied by combined in situ time-resolved XRD and mass spectroscopy

    SciTech Connect

    Bak, Seong-Min [Brookhaven National Lab. (BNL), Upton, NY (United States); Hu, Enyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhou, Yongning [Brookhaven National Lab. (BNL), Upton, NY (United States); Yu, Xiqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cho, Sung-Jin [Johnson Control Advanced Power Solution, Milwaukee, WI (United States); North Carolina A& T State Univ., Greensboro, NC (United States); Kim, Kwang-Bum [Yonsei Univ., Seoul (Republic of Korea); Chung, Kyung Yoon [Korea Inst. of Science and Technology, Seoul (Republic of Korea); Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States); Nam, Kyung-Wan [Dongguk Univ., Seoul (Republic of Korea)

    2014-12-24

    Thermal stability of charged LiNixMnyCozO? (NMC with x+y+z=1, x:y:z = 4:3:3 (NMC433), 5:3:2 (NMC532), 6:2:2 (NMC622), and 8:1:1 (NMC811)) cathode materials is systematically studied using combined in situ time resolved X-ray diffraction and mass spectroscopy (TR- XRD/MS) techniques upon heating up to 600 °C. The TR-XRD/MS results indicate that the content of Ni, Co, and Mn significantly affects both the structural changes and the oxygen release features during heating: the more Ni and less Co and Mn, the lower the onset temperature of the phase transition (i.e., thermal decomposition) and the larger amount of oxygen release. Interestingly, the NMC532 seems to be the optimized composition to maintain a reasonably good thermal stability comparable to the low Ni-content materials (e.g., NMC333 and NMC433) while having a high capacity close to the high Ni-content materials (e.g., NMC811 and NMC622). The origin of the thermal decomposition of NMC cathode materials was elucidated by the changes in the oxidation states of each transition metal (TM) cations (i.e., Ni, Co and Mn) and their site preferences during thermal decomposition. It is revealed that Mn ions mainly occupy the 3a octahedral sites of layered structure (R3m ) but Co ions prefer to migrate to the 8a tetrahedral sites of spinel structure (Fd3m ) during the thermal decomposition. Such elemental dependent cation migration plays a very important role for the thermal stability of NMC cathode materials. The reasonably good thermal stability and high capacity characteristics of the NMC532 composition is originated from the well-balanced ratio of Ni- to Mn- and Co- contents. This systematic study provides insight into the rational design of NMC based cathode materials with a desired balance between thermal stability and high energy density

  9. Electrically Tunable Magnetism in Magnetic Topological Insulators

    NASA Astrophysics Data System (ADS)

    Zhang, Shou-Cheng; Wang, Jing; Lian, Biao

    2015-03-01

    The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modication of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a topological transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. The simultaneous electrical control of magnetic order and chiral edge transport in such a device may lead to electronic and spintronic applications for topological insulators. This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515.

  10. Nanocomposite Magnets: Transformational Nanostructured Permanent Magnets

    SciTech Connect

    None

    2010-10-01

    Broad Funding Opportunity Announcement Project: GE is using nanomaterials technology to develop advanced magnets that contain fewer rare earth materials than their predecessors. Nanomaterials technology involves manipulating matter at the atomic or molecular scale, which can represent a stumbling block for magnets because it is difficult to create a finely grained magnet at that scale. GE is developing bulk magnets with finely tuned structures using iron-based mixtures that contain 80% less rare earth materials than traditional magnets, which will reduce their overall cost. These magnets will enable further commercialization of HEVs, EVs, and wind turbine generators while enhancing U.S. competitiveness in industries that heavily utilize these alternatives to rare earth minerals.

  11. Magnetization dynamics in ultrathin magnetic films

    Microsoft Academic Search

    Oleksandr Mosendz

    2008-01-01

    Ultrathin magnetic multilayer structures are prepared by Molecular Beam Epitaxy (MBE) on GaAs(001) substrates. Growth was monitored and characterized by Reflection High Energy Electron Diffraction (RHEED), Auger Electron Spectroscopy (AES), X-Ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM). The Fe\\/GaAs interface and its influence on the static magnetic properties in magnetic ultrathin films was studied by means of Ferromagnetic

  12. Size effect on the magnetic properties of oleic acid stabilized substrate free BiFeO3 nanocrystals

    NASA Astrophysics Data System (ADS)

    Mahesh, Dabbugalla; Mahato, Bipul K.; Barman, Anjan; Mandal, Swapan K.

    2015-04-01

    We report here on the unique synthesis of BiFeO3 (BFO) nanocrystals of different size by using oleic acid as a capping agent and investigate the structural and magnetic properties. Oleic acid is found to be a good stabilizing agent to obtain different crystal size and distributions of BFO nanocrystals. Structural characterizations by X-ray diffraction (XRD) reveal the phase purity of all the samples. The BFO nanocrystals display strong size dependent magnetic properties showing increase in both magnetization (Ms) as well as in coercive field (Hc) with decreasing the crystal size due to the size confinement effect as well as change in magnetocrystalline anisotropy. The smallest BFO nanocrystal of size ~12 nm shows remarkably high (8.17 emu/g) magnetization value compared to previous reports. The results obtained here will be of immense important for advanced applications in electromagnetic devices.

  13. Magnetic studies of mesoporous nanostructured iron oxide materials synthesized by one-step soft-templating.

    PubMed

    Jin, Jing; Hines, William A; Kuo, Chung-Hao; Perry, David M; Poyraz, Altug S; Xia, Yan; Zaidi, Taha; Nieh, Mu-Ping; Suib, Steven L

    2015-07-14

    A combined magnetization and (57)Fe spin-echo nuclear magnetic resonance (NMR) study has been carried out on mesoporous nanostructured materials consisting of the magnetite (Fe3O4) and maghemite (?-Fe2O3) phases. Two series of samples were synthesized using a recently developed one-step soft-templating approach with systematic variations in calcination temperature and reaction atmosphere. Nuclear magnetic resonance has been shown to be a valuable tool for distinguishing between the two magnetic iron oxide spinel phases, Fe3O4 and ?-Fe2O3, on the nanoscale as well as monitoring phase transformation resulting from oxidation. For the Fe3O4 and ?-Fe2O3 phases, peaks in the NMR spectra are attributed to Fe in the tetrahedral (A) sites and octahedral (B) sites. The magnetic field dependence of the peaks was observed and confirmed the site assignments. Fe3O4 on a nanoscale readily oxidizes to form ?-Fe2O3 and this was clearly evident in the NMR spectra. As evidenced by transmission electron microscope (TEM) images, the porous mesostructure for the iron oxide materials is formed by a random close-packed aggregation of nanoparticles; correspondingly, superparamagnetic behavior was observed in the magnetic measurements. Although X-ray diffraction (XRD) shows the spinel structure for the Fe3O4 and ?-Fe2O3 phases, unlike NMR, it is difficult to distinguish between the two phases with XRD. Nitrogen sorption isotherms characterize the mesoporous structures of the materials, and yield BET surface area values and limited BJH pore size distribution curves. PMID:26067028

  14. Magnetic measurements of the XLS magnets

    SciTech Connect

    Solomon, L.; Galayda, J.; Sylvester, C.

    1991-01-01

    The magnets designed and built for Phase 1 (200MeV) of the XLS (X-Ray Lithography Source) project have all been measured and characterized. In this paper, the measurement system designed and utilized for the Phase 1 180 degree dipole magnets is reviewed. Hall probe measurements of the two dipole magnets, with a field of 1.1 Tesla at 1200 amperes, are discussed and presented. Phase 2 (700MeV) of this project includes replacement of the two room temperature dipole magnets with superconducting dipoles (3.9Tesla). 3 figs., 1 tab.

  15. An overview of magnetism of spinel nanoferrite particles and A study of chromium substituted Zn-Mn ferrites nanostructures via sol-gel method

    Microsoft Academic Search

    C Ramesh; Maniysundar

    2011-01-01

    In this review article, we attempt to describe the structure of various spinel ferrites like zinc ferrite, nickel-zinc ferrite, manganese-zinc ferrite and cobalt ferrite. It also describes the important magnetic properties of these spinel ferrites. The article also focused Nanocrystalline ZnMn1?xCrxFeO4 (1.0 >x > 0) ferrites which were prepared by sol-gel route. The detailed results of XRD, SAED and infrared

  16. The effect of Ni substitution on magnetic, dielectric and magnetoelectric properties in BiFe 1? x Ni x O 3 system

    Microsoft Academic Search

    Amit Kumar; K. L. Yadav

    2010-01-01

    Multiferroic nanoceramics BiFe1?xNixO3 (where x=0, 0.15, 0.20, and 0.25) were prepared by the sol–gel method. XRD analysis of samples calcined at a low temperature of 400°C for 2h shows the formation of a single phase perovskite rhombohedral structure. Average particle size was observed to be ?50nm by TEM measurement. Magnetization was found to increase with increase in the concentration of

  17. Effect of Post Annealing on the Microstructure and Magnetic Properties of NdFe BP?2FePNdFe B Thin Films

    Microsoft Academic Search

    Yi Meiqing

    2008-01-01

    A series of nanocomposite thin films , composed of Nd2Fe14B and? 2Fe , has been prepared by DC2magnetron sputtering combined ion beam sputtering onto Si (100) substrates . The effects of post annealing on the microstructure and magnetic properties of ( NdFeBP? 2FeP NdFeB )2type thin films have been investigated . The X2ray diffraction ( XRD) study showed that annealing

  18. Correlation between saturation magnetization, bandgap, and lattice volume of transition metal (M=Cr, Mn, Fe, Co, or Ni) doped Zn1-xMxO nanoparticles

    Microsoft Academic Search

    J. Anghel; A. Thurber; D. A. Tenne; C. B. Hanna; A. Punnoose

    2010-01-01

    This work reports on transition metal doped ZnO nanoparticles and compares the effects doping with different transition metal ions has on the structural, optical, and magnetic properties. Zn1-xMxO (M=Cr, Mn, Fe, Co, or Ni) nanoparticles were prepared by a chemical process for x=0.02 and 0.05 in powder form. The powders where characterized by x-ray diffraction (XRD), spectrophotometry, and magnetometry. The

  19. The precipitation sequence obtained during crystallization of an amorphous Co 65Si 15B 14Fe 4Ni 2 magnetic alloy

    Microsoft Academic Search

    H. F Li; R. V Ramanujan

    2004-01-01

    The microstructures developed during crystallization of an initially amorphous Co65Si15B14Fe4Ni2 magnetic alloy were investigated using transmission electron microscopy, X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The microstructural evolution involved at least three steps: (a) primary precipitation from an amorphous matrix; (b) nanoprecipitation at primary precipitate's boundaries as well as inside the primary precipitates; (c) heterogeneous microstructures. At 600 °C

  20. Journal of Magnetism and Magnetic Materials 293 (2005) 578583 Theoretical comparison of magnetic and hydrodynamic

    E-print Network

    2005-01-01

    ). #12;inhomogeneous magnetic field created by micro- structures that are magnetized by either electro- magnets or a permanent magnet. The structures are small so that they make large gradientsJournal of Magnetism and Magnetic Materials 293 (2005) 578­583 Theoretical comparison of magnetic

  1. The synthesis, molecular structure, FT-IR and XRD spectroscopic investigation of 4-[(2-{[(2-furylmethyl)imino]methyl}-4-methoxyphenoxy)methyl]benzonitrile: A comparative DFT study

    NASA Astrophysics Data System (ADS)

    Alver, Özgür; Hayval?, Zeliha; Güler, Hüseyin; Dal, Hakan; ?enyel, Mustafa

    2011-04-01

    4-[(2-{[(2-Furylmethyl)imino]methyl}-4-methoxyphenoxy)methyl]benzonitrile, a novel Schiff base compound, was prepared for the first time and its structural and vibrational properties were studied both experimentally and theoretically using FT-IR and XRD spectroscopic methods. FT-IR spectrum was recorded in the region of 4000-400 cm -1. The optimized geometric structures concerning to the minimum on the potential energy surface was investigated by Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional theory method together with 6-31(d) basis set. Vibrational wavenumbers were calculated using B3LYP/6-31G(d) level of theory. Comparison between the experimental and theoretical results indicates that density functional B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers and structural parameters of the prepared Schiff base compound. Furthermore, reliable vibrational assignments were made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method.

  2. Fabrication and characterization of ZnO@CdS core-shell nanostructure using acetate precursors: XRD, FESEM, DRS, FTIR studies and effects of cadmium ion concentration on band gap

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Rahmati, Mohammad Hossein

    2014-12-01

    ZnO@CdS core-shell nano-structure has been synthesized using zinc acetate dihydrate, and cadmium acetate dihydrate as simple precursors in a water-ethanol matrix without using any surfactant, ligand or chelating agents. The effect of different concentrations of cadmium acetate and sodium sulfide on optical and electronic properties of ZnO@CdS core-shell was investigated. The morphology and structure of the ZnO@CdS core-shell nano-structures have been confirmed by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements. The results showed that the ZnO@CdS core-shell nano-structure is mixed cubic and hexagonal structures. FESEM results showed the mono-dispersed and uniform size of 39 nm. Optical properties were studied by UV-visible diffuse reflectance spectroscopy (DRS) technique and the results showed that band gaps of ZnO@CdS core-shell nanocomposites were red shifted by increasing the cadmium concentration. FTIR spectrum of ZnO@CdS core-shell nano-structure showed a band at 482 cm-1 correlated to Znsbnd O bond and a band at 630 cm-1 due to the stretching frequency of Cdsbnd S bond.

  3. Spectral, thermal, XRD and SEM studies of charge-transfer complexation of hexamethylenediamine and three types of acceptors: ?-, ?- and vacant orbital acceptors that include quinol, picric acid, bromine, iodine, SnCl4 and ZnCl2 acceptors

    NASA Astrophysics Data System (ADS)

    Adam, Abdel Majid A.; Refat, Moamen S.; Saad, Hosam A.

    2013-11-01

    In this work, structural, thermal, morphological and pharmacological characterization was performed on the interactions between a hexamethylenediamine (HMDA) donor and three types of acceptors to understand the complexation behavior of diamines. The three types of acceptors include ?-acceptors (i.e., quinol (QL) and picric acid (PA)), ?-acceptors (i.e., bromine and iodine) and vacant orbital acceptors (i.e., tin(IV) tetrachloride (SnCl4) and zinc chloride (ZnCl2)). The characterization of the obtained CT complexes was performed using elemental analysis, infrared (IR), Raman, 1H NMR and electronic absorption spectroscopy, powder X-ray diffraction (XRD) and thermogravimetric (TG) analysis. Their morphologies were studied using scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). The biological activities of the obtained CT complexes were tested for their antibacterial activities. The complex containing the QL acceptor exhibited a remarkable electronic spectrum with a strong, broad absorption band, which had an observed ?max that was at a much longer wavelength than those of the free reactants. In addition, this complex exhibited strong antimicrobial activities against various bacterial and fungal strains compared to standard drugs. The complexes containing the PA, iodine, Sn(IV) and Zn(II) acceptors exhibited good thermal stability up to 240, 330, 275 and 295 °C, respectively. The complexes containing bromine, Sn(IV) and Zn(II) acceptors exhibited good crystallinity. In addition to its good crystallinity properties, the complex containing the bromine acceptor exhibits a remarkable morphology feature.

  4. The Magnetic Sun

    NSDL National Science Digital Library

    David Stern

    This lesson presents an overview of phenomena related to the magnetism of the Sun, in particular to sunspots and their 11-year cycle, solar flares and magnetic disturbances on Earth caused by solar activity. It also reviews briefly the connection between electricity and magnetism. Students will learn facts about the discovery of sunspots, their intense magnetism, and their 11-year cycle. They will be introduced to solar activity associated with sunspots and their cycles, e.g. the abrupt brightenings known as solar flares. They also learn that solar activity is probably associated with the release of magnetic energy, and that such releases can propel fast plasma flows towards Earth, causing magnetic storms.

  5. The Magnetic Field

    NSDL National Science Digital Library

    Windows to the Universe

    1997-12-03

    This webpage is part of the University Corporation for Atmospheric Research (UCAR) Windows to the Universe program. It describes the nature and configuration of magnetic fields, which are the result of moving electric charges, including how they cause magnetic objects to orient themselves along the direction of the magnetic force points, which are illustrated as lines. Magnetic field lines by convention point outwards at the north magnetic pole and inward at the south magnetic pole. The site features text, scientific illustrations and an animation. Text and vocabulary are selectable for the beginning, intermediate, or advanced reader.

  6. Transformation kinetics & magnetism of magnetite nanoparticles

    NASA Astrophysics Data System (ADS)

    Laurenzi, Mark Anthony, III

    This dissertation presents the results of a study of the nucleation and growth kinetics and magnetic properties of iron-oxide based nanoparticles that are formed by crystallization of a Na-Ca borate amorphous precursor. In addition to the interesting phase transformation kinetics and concentration dependent growth phenomena observed in this system, it also provides an opportunity to study finite-size effects on the magnetic properties of single domain particles. The crystallization of iron oxide nanoparticles and the phase identity (magnetite or maghemite) upon heat treatment was investigated over a range of time, temperature, and redox conditions. X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron diffraction (ED) were used to structurally characterize the resulting nanoparticles. Magnetite formation was favored under more reducing conditions whereas maghemite was formed under more oxidizing conditions. Under all conditions investigated, the particle size fell in the narrow range of about 2.5 to 4.5 nm and showed no evidence of further growth with time. This is believed to result from the increased viscosity in the iron-depleted diffusion field surrounding each particle. The magnetic properties were characterized using a superconducting quantum interference device (SQUID) and Mossbauer spectrometer (MS). Magnetization measurements were made from room temperature down to ˜10 K under field-cooled (FC) and zero-field-cooled (ZFC) conditions. The average blocking temperature obtained from these measurements is generally consistent with the measured particle size for reasonable values of the anisotropy constant. Unlike maghemite, bulk magnetite exhibits a metal-insulator transition, first reported by Verwey in 1939. The effect was attributed by Verwey and others to a charge-ordering transition. However, very recent data suggest that the Verwey transition is instead associated with a structural transition from inverse to normal spinel. In the present work, the magnetization data for samples produced under more reducing conditions show clear evidence of a Verwey transition in 4--4.5 nm magnetite nanoparticles. However, the transition is found to be shifted from the bulk value of ˜120 K to 85--95 K, which is attributed to finite-size effects.

  7. Co-precipitation synthesis of Cox2+Fe1-x2+Fe2O4 nanoparticles: Structural characterization and magnetic properties

    NASA Astrophysics Data System (ADS)

    Soleimani, Hassan; Yahya, Noorhana; Latiff, Noor Rasyada Ahmad; Sabet, Maziyar; Guan, Beh Hoe; Chuan, Lee Kean

    2014-10-01

    Cobalt ferrite is known as a promising magnetic material for various applications. This metal-ceramic composite (Cox2+Fe1-x2+Fe2O4) was synthesized via co-precipitation route, by varying the Co/Fe ratios (Co/Fe = 0.3, 0.2, and 0). The structures and magnetic properties of nano-composites were analyzed by XRD and VSM. As deduced from the XRD line broadening, the average crystallite size of the samples was found to be in the range of 13.0-15.0 nm and contain fcc structure with smaller lattice constant as the Co/Fe ratios increases. FESEM and TEM images revealed the morphology of the samples, which consist of irregular shapes of diameter in the range of 9.0-15.0 nm. Magnetic properties measurement shows that sample S11 with the highest Co/Fe ratio has the highest value of saturation magnetization (Ms) of 65.23 emu/g. On the other hand, increase in the concentration of cobalt ions improves the remanence magnetization (Mr) and coercivity (Hc) of the same sample to 12.18 emu/g and 238.92 Oe, respectively. It is demonstrated that the higher substitution ratio of cobalt in Cox2+Fe1-x2+Fe2O4 has successfully improve the magnetic properties of the samples.

  8. Co doped ZnO semiconductor materials: structural, morphological and magnetic properties

    Microsoft Academic Search

    Adriana Popa; Dana Toloman; Oana Raita; Alexandru Radu Biris; Gheorghe Borodi; Thikra Mustafa; Fumiya Watanabe; Alexandru Sorin Biris; Alexandru Darabont; Liviu Mihail Giurgiu

    Structural, morphological and magnetic properties of Zn1?xCoxO (x = 0.01 and 0.03) powdered materials are presented. XRD studies reveal a wurtzite-type structure, while the formation\\u000a of a Co3O4 secondary phase was evidenced by Raman spectroscopy. A ferromagnetic behaviour with low Curie temperature was evidenced by\\u000a Electron Paramagnetic Resonance (EPR) investigation. We suggest that the origin of the ferromagnetism in Zn1?xCoxO

  9. Research on La3+ Co2+-substituted strontium ferrite magnets for high intrinsic coercive force

    Microsoft Academic Search

    Xiansong Liu; Pablo Hernández-Gómez; Kai Huang; Shengqiang Zhou; Yong Wang; Xia Cai; Hongjun Sun; Bao Ma

    2006-01-01

    M-type strontium ferrites with substitution of Sr2+ by rare-earth La3+, and a little amount of Fe3+ by Co2+ according to the formula Sr1-xLaxFe12-xCoxO19, are prepared by the ceramic process. Effects of the substituted amount of La3+ and Co2+ on structure and magnetic properties of Sr1-xLaxFe12-xCoxO19 compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and B

  10. Research on La 3+–Co 2+-substituted strontium ferrite magnets for high intrinsic coercive force

    Microsoft Academic Search

    Xiansong Liu; Pablo Hernández-Gómez; Kai Huang; Shengqiang Zhou; Yong Wang; Xia Cai; Hongjun Sun; Bao Ma

    2006-01-01

    M-type strontium ferrites with substitution of Sr2+ by rare-earth La3+, and a little amount of Fe3+ by Co2+ according to the formula Sr1?xLaxFe12?xCoxO19, are prepared by the ceramic process. Effects of the substituted amount of La3+ and Co2+ on structure and magnetic properties of Sr1?xLaxFe12?xCoxO19 compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and B–H

  11. Magnetic properties and high frequency characteristics of FeCoAlON alloy films

    NASA Astrophysics Data System (ADS)

    Zheng, Kuohai; Yang, Shengsheng; Zheng, Fu; Luo, Feilong; Bai, Jianmin; Cao, Jiangwei; Wei, Fulin

    2015-06-01

    In this work, we report the magnetic properties, domain structures and high frequency properties of FeCoAlON alloy films prepared by reactive magnetron sputtering. With increasing N addition content, the films transfer from in-plane anisotropic properties to isotropic behavior. The obvious stripe domain structure is observed in the films with high N content, and the domain parameters depend on the thickness of the films. The XRD analysis indicates that the stripe domain may origin from the stress-induced perpendicular anisotropy by Al, O and N addition. Meanwhile, a double-peak resonance behavior is observed in the permeability spectra of the films with stripe domain structure.

  12. Structural and magnetic properties of a stage-2 HoCl 3-graphite intercalation compound

    Microsoft Academic Search

    S. Cahen; R. Vangelisti; C. Bellouard

    2006-01-01

    A stage-2 HoCl3-GIC has been synthesized and characterized by XRD experiments and magnetic measurements. EDS and 00l X-ray analyses lead to the chemical formula C23.8HoCl3.7.The c-axis repeat distance is 1313±5pm, and the stacking sequence of intercalated HoCl3 along the c-axis corresponds to the layer sandwich Cl–Ho–Cl, where the distance between Ho and Cl layers is 157pm. The HoCl3 in-plane structure

  13. Spherical magnetic nanoparticles: magnetic structure and interparticle interaction

    E-print Network

    Paris-Sud XI, Université de

    made of soft magnetic material (permalloy as an example) when they reach the vortex regime. We considerSpherical magnetic nanoparticles: magnetic structure and interparticle interaction V. Russier The interaction between spherical magnetic nanoparticles is investigated from micromagnetic simulations

  14. Magnetic response of polycrystalline YBaCo4O7+? synthesized through the physical and chemical route: The role of phase inhomogeneities

    NASA Astrophysics Data System (ADS)

    Vallejos, E.; Galeano, V.; Gómez, L.; Izquierdo, J. L.; Montoya, J. F.; Mera, J.; Córdoba, C.; Gómez, A.; Paucar, C.; Morán, O.

    2014-06-01

    Polycrystalline YBaCo4O7+? samples were obtained through a standard solid state reaction, and their structural, morphological, electrical, and magnetic properties are carefully studied. The X-ray powder diffraction (XRD) patterns showed reflections of a pure hexagonal structure (space group P63mc) with lattice parameters being very close to those reported in the literature. Although XRD analysis showed that the main phase present is 114, the presence of secondary phases could not be ruled out based solely on the XRD characterization. Indeed, sensitive SQUID magnetic measurements showed that the samples were affected by very small quantities of the 112 phase (YBaCo2O5.5), which typically manifests itself through a conspicuous increase in the magnetization at~300 K. The results achieved corroborated the predictions concerning the difficulty of stabilizing the 114 phase when synthesized via the standard solid-state reaction. With this in mind, we next attempted to obtain the compound with improved phase purity. In so doing, the YBaCo4O7+? compound was synthesized through a wet chemistry method based on a citrates route. The XRD patterns recorded for these samples revealed well-defined peaks corresponding to a pure hexagonal structure. More interestingly, SQUID measurements show no sign of features in the M(T) curve at temperatures as low as~80 K. This result was consistent with the magnetic behavior observed in YBaCo4O7+? single-crystals. At temperatures below~80 K, a clear feature was observed which seemed to correlate with a transition into an antiferromagnetic state. Isothermal magnetization recorded at 70 K showed that field-induced effects manifested themselves through the appearance of a ferromagnetic-like component. This ferromagnetic component may arise from spin canting of the underlying antiferromagnetic state or through field-induced structural transition (at least at local scale). Although a definitive interpretation of the in-field behavior from magnetization data alone is difficult because of the unknown role of the yttrium ion, the results achieved suggest that the magnetic behavior observed in members of the R-114 family is not necessarily linked to the moment of the rare-earth ion, as in case of YBaCo4O7+?, since the yttrium ion is not magnetic. Beyond this important finding, the experimental results reported in the present paper demonstrate that the tested chemical route is suitable for synthesizing complex, single-phase oxides, such as the YBaCo4O7+? cobaltate. The success in synthesizing high-purity YBaCo4O7+? allows one to subtract parasitic effects from the intrinsic magnetic behavior of this challenging system.

  15. Structural, electronic and magnetic properties of Mo (4d)-based complex perovskites Ba2MMoO6 (M=Cr and Fe)

    NASA Astrophysics Data System (ADS)

    Musa Saad H.-E., M.; El-Hagary, M.

    2014-06-01

    We report a study of crystallographic parameters of the Mo-based complex perovskites Ba2MMoO6 (M=Cr and Fe) obtained from analysis of X-ray diffraction (XRD) data and the electronic and magnetic properties prediction using the magnetic measurements and the full-potential linearized muffin-tin orbitals within the plane-wave approximation (LMTO-PLW). The Ba2MMoO6 materials were prepared by the solid state reaction method. XRD analysis reveals that Ba2MMoO6 crystalline in a cubic structure (space group Fm-3m) with lattice parameters (a=8.013 Å) for M=Cr and (a=8.061 Å) for M=Fe. XRD results present a matching of 98% with the theoretical results. The densities of states were calculated using the local spin density approximation (LSDA) and LSDA+U methods. LDOS results show a half-metallic-ferrimagnetic ground state for Ba2MMoO6, which is in majority due to the 4d-t2g and 3d-t2g characters. The structural, electronic and magnetic calculation results are in excellent agreement with the experimental and previous theoretical results.

  16. Effect of Cr substitution on the superconducting and magnetic properties of RuSr2Eu1.5Ce0.5Cu2O10-?

    NASA Astrophysics Data System (ADS)

    Kumar, Anuj; Mudgel, Monika; Awana, V. P. S.; Kishan, Hari

    2010-12-01

    In this paper we investigate the properties of polycrystalline series of Ru1-xCrxSr2Eu1.5Ce0.5Cu2O10-? (0.0 ? x ? 0.40) by resistivity, XRD and dc magnetization measurements. EuRu-1222 is a reported magneto superconductor with Ru spins magnetic ordering at temperatures near 100 K and superconductivity occurs in Cu-O2 planes below Tc ? 40 K. The exact nature of Ru spins magnetic ordering is still being debated and no conclusion has been reached yet. In this work, we found the superconducting transition temperature Tc = 20 K from resistivity and dc magnetization measurements for pristine sample. DC magnetization measurements exhibited ferromagnetic like transition for all samples.

  17. Effect of Cr substitution on the superconducting and magnetic properties of RuSr 2Eu 1.5Ce 0.5Cu 2O 10-?

    NASA Astrophysics Data System (ADS)

    Kumar, Anuj; Mudgel, Monika; Awana, V. P. S.; Kishan, Hari

    In this paper we investigate the properties of polycrystalline series of Ru 1-xCr xSr 2Eu 1.5Ce 0.5Cu 2O 10-? (0.0 ? x ? 0.40) by resistivity, XRD and dc magnetization measurements. EuRu-1222 is a reported magneto superconductor with Ru spins magnetic ordering at temperatures near 100 K and superconductivity occurs in Cu-O 2 planes below Tc ? 40 K. The exact nature of Ru spins magnetic ordering is still being debated and no conclusion has been reached yet. In this work, we found the superconducting transition temperature Tc = 20 K from resistivity and dc magnetization measurements for pristine sample. DC magnetization measurements exhibited ferromagnetic like transition for all samples.

  18. Crystallographic and magnetic properties of fine iron nitride powders prepared by solid state reactions between iron and organic H{sub x}(CN)-ring compounds

    SciTech Connect

    Kaczmarek, W.A. [Australian National Univ., Canberra (Australia). Research School of Physical Sciences and Engineering] [Australian National Univ., Canberra (Australia). Research School of Physical Sciences and Engineering

    1995-12-01

    In this work morphological, crystallographic and magnetic properties of iron nitride powders prepared by room temperature mechano-chemical processing, were studied by SEM, XRD and VSM methods. Nitridation reaction occurs during ball milling of a stoichiometric mixture of {alpha}Fe powder and highly reactive complex amine compounds: piperazine, pyrazine and pyrazole in the molar ratio 3:1 (Fe:N). The amount of nitride phase produced, depends on milling time, annealing temperature and on the chemical reactivity of the amine compound with iron. Calculation of crystal lattice parameters show that prepare nitrides are similar to stoichiometric Fe{sub 3}N hcp type structure. Lattice expansion was found for hexagonal planes due to increasing nitrogen concentration. Magnetic hysteresis parameters were found to be very sensitive to changes in chemical composition. As the amount of nitrogen increases magnetic remanence and coercivity increase but magnetization and calculated average magnetic moment per Fe atom decrease.

  19. Influence of pH on the structural and magnetic behavior of cobalt ferrite synthesized by sol-gel auto-combustion

    NASA Astrophysics Data System (ADS)

    Kakade, S. G.; Kambale, R. C.; Kolekar, Y. D.

    2015-06-01

    Cobalt ferrite (CoFe2O4) shown to be promising candidate for applications such as high-density magnetic recording, enhanced memory storage, magnetic fluids and catalysts. Utility of ferrite nanoparticles depends on its size, dispersibility in solutions, and magnetic properties. We have investigated the structural properties of synthesized cobalt ferrite nanoparticles synthesized by sol gel auto combustion for uncontrolled, acidic, neutral and basic pH values. X-ray diffraction (XRD) study confirms the cubic spinel phase formation with lattice constant 8.38 Å. In this study, we have optimized the pH value to synthesize homogenous cobalt ferrite nanoparticles with enhanced magnetic behavior. The surface morphology has been investigated by employing SEM images and the confirmation of spinel ferrite was also supported by using IR spectroscopy. Magnetic measurements for CoFe2O4 compositions (with pH <1, pH = 3, 7, 10) were investigated using VSM measurements.

  20. Spin and orbital magnetization loops obtained using magnetic Compton scattering

    SciTech Connect

    Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Koizumi, A. [Graduate School of Materials Science, University of Hyogo, Hyogo 678-1297 (Japan)] [Graduate School of Materials Science, University of Hyogo, Hyogo 678-1297 (Japan)

    2013-02-25

    We present an application of magnetic Compton scattering (MCS) to decompose a total magnetization loop into spin and orbital magnetization contributions. A spin magnetization loop of SmAl{sub 2} was measured by recording the intensity of magnetic Compton scattering as a function of applied magnetic field. Comparing the spin magnetization loop with the total magnetization one measured by a vibrating sample magnetometer, the orbital magnetization loop was obtained. The data display an anti-coupled behavior between the spin and orbital magnetizations and confirm that the orbital part dominates the magnetization.