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AbstractAbstract
[en] New compounds belonging to the BiSrCaCuO cuprate family have been synthesized by sequentially imposed layer epitaxy. The Cu/Ca ratio in these compounds is typically twice the value for conventional Bi2Sr2Can-1Cun+4. A second characteristic of the new compounds is a Bi deficiency relative to conventional BSCCO. The room temperature electrical resistivity of these compounds reaches extremely low values, orders of magnitude below that of copper. Strongly non-linear I(V) characteristics of various forms are observed; Typical examples are describes where the voltage dependence at the onset of measurable dissipation is either exponential or parabolic as a function of current intensity. Examples are also presented I(V) exhibits and hysteric behavior. (authors)
Original Title
Proprietes de transport a la temperature ambiante de nouveaux composes BiSrCaCuO
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51 refs.
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Journal Article
Journal
Comptes Rendus de l'Academie des Sciences. Serie 2, Mecanique, Physique, Chimie, Astronomie; ISSN 1251-8069;
; CODEN CMCAEK; (no.10-t.324); p. 627-639

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Venturini, E.L.; Bowman, R.C. Jr.; Craft, B.D.; Tadlock, W.E.; Cantrell, J.S.
Sandia National Labs., Albuquerque, NM (USA); Monsanto Research Corp., Miamisburg, OH (USA). Mound; Miami Univ., Oxford, OH (USA). Dept. of Chemistry1984
Sandia National Labs., Albuquerque, NM (USA); Monsanto Research Corp., Miamisburg, OH (USA). Mound; Miami Univ., Oxford, OH (USA). Dept. of Chemistry1984
AbstractAbstract
[en] The proton spin-lattice relaxation times (T1) and magnetic susceptibilities (X) are used to study the effects of hydrogen on the electronic structure properties of the intermetallic TiCo. Hydrogen addition systematically decreases both X(T) and the proton (T1T)/sup 1/2/ parameters, which are directly proportional to the local density of the Fermi level electronic states. The behavior for TiCoH/sub x/ is completely opposite to that previously found for several other Ti-based metal hydrides where these parameters tend to increase with hydrogen content. These differences are attributed to the Fermi levels falling on alternate sides of peaks in the densities of electronic states. The present results for TiCoH/sub x/ are compared with the magnetic properties and the theoretical band structures for the closely related hydride TiFeH/sub x/
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1984; 15 p; Magnetism and magnetic materials conference and exhibit; San Diego, CA (USA); 27-30 Nov 1984; CONF-841184--2; Available from NTIS, PC A02/MF A01 as DE85000668
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AbstractAbstract
[en] The project was carried out in relation to possible cable and electronics applications of high-Tc materials. Laser ablation was used as the deposition technique because of its stoichiometry conservation. Films were made in the YBa2Cu3O7 compound due to its relatively simple stoichiometry compared to other High-Tc compounds. Much attention was paid to the critical current density. A very high critical current density was reached. By using texture analysis by X-ray diffraction, it was found that films with high critical current densities were epitaxial, while films with low critical current densities contained several crystalline orientations. Four techniques for patterning the films were used - photo lithography and wet etch, laser ablation lithography, laser writing and electron beam lithography and ion milling. Sub-micron patterning has been demonstrated without degradation of the superconducting properties. The achieved patterning resolution is sufficient for preparation of many superconducting components. (AB)
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Aug 1991; 176 p
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Miscellaneous
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Mirebeau, I.; Hennion, M.; Dianoux, J.; Caignaert, V.; Moorjani, K.
Laboratoire Leon Brillouin (LLB) - Centre d'Etudes Nucleaires de Saclay, 91 -Gif-sur-Yvette (France)1989
Laboratoire Leon Brillouin (LLB) - Centre d'Etudes Nucleaires de Saclay, 91 -Gif-sur-Yvette (France)1989
AbstractAbstract
[en] We have studied the dynamics of the iron spins in a superconducting YBa2(Cu0.94Fe0.06)3O7 sample by neutron time of flight measurements. The range of scattering vector q was 0.1 < Q < 2.1 A-1, and the energy resolution 80 μeV. The temperature was varied in the range 1.8 K < T < 300 K. In the whole temperature range, the q-dependence of the magnetic intensity mainly reflects the magnetic form factor of iron which shows that the iron spins are almost uncorrelated. The elastic and quasielastic intensities strongly vary with temperature. A spin glass like freezing is revealed at low temperature by a sharp decrease of the quasielastic intensity, an increase of the elastic or resolution limited intensity and a minimum in the quasielastic width. The freezing temperature (Tf = 18 K) corresponds to that already determined by a magnetic splitting in Moessbauer experiments. Above Tf, the relaxation of the iron spins in the paramagnetic state is modified by the occurrence of superconductivity. We observe a slight increase of the quasielastic intensity and of the quasielastic width at the superconducting transition (Tc = 74 K), possibly related to the electron-spin coupling
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1989; 11 p; 34. Annual Conference on Magnetism and Magnetic Materials; Boston, MA (USA); 28 Nov - 1 Dec 1989
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Saitovitch, E.B.; Scorzelli, R.B.; Azevedo, I.S.; Micklitz, H.
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro (CBPF), RJ (Brazil)1989
Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro (CBPF), RJ (Brazil)1989
AbstractAbstract
[en] In situ high temperature 57Fe Moessbauer measurements were performed on samples of YBa2(Cu1-xFex3O7-δ, in pure oxygen or in air, both at a pressure of about 1 atm. Three samples were studied with x = 0.005 and 0.010, respectively in the temperature range from 295 to 640 K. As in previously published papers, the fitted quadrupole doublets were associated to different oxygen configurations around the Fe ions on the Cu(1) chain site, whose temperature dependent behavior can be summarized: i) the f-factor for the different configurations are very similar; ii) the effective Debye temperature (≅ 350 k) is rather insensitive to the Fe content and oxygen coordination; iii) the electronic configuration of Fe is very stable up 320 C; iv) the quadrupole splitting q(T) can be well described within the picture use for non cubic metals, Finally a partial change from doublet A to B induced by temperatures is observed. This change is completely or partially reversible, depending on the sample. (author)
[pt]
Medidas Moessbauer do 57Fe a alta temperatura in situ foram feitas sobre amostras de YBa2(Cu1-xFex)3O7-δ, em oxigenio puro ou em ar, ambos a pressao de 1 atm. Tres amostras foram estudadas com x=0.005 e 0,010, respectivamente no intervalo de temperatura de 295 a 640 K. Como em artigos publicados anteriormente. Os doublets de quadrupolo ajustados foram associados a diferentes configuracoes do oxigenio em torno dos ions de Fe sobre a cadeia local de Cu(1), cujo comportamento dependente da temperatura pode ser resumido: i) o fator-f para as diferentes configuracoes sao muito similar; ii) a temperatura efetiva de Debye (≅ 350 K) e menos suscetivel ao conteudo de ferro e coordenacao do oxigenio; iii) a configuracao eletronica do Fe e mais estavel ate 3200C; iv) a divisao do quadrupolo q (T) pode ser bem descrita dentro do quadro usado para metais nao cubicos. Finalmente uma variacao do doublet A para B induzido pela temperatura e observado. Esta variacao e completamente ou parcialmente versivel dependendo da amostra. (M.C.K.)Primary Subject
Source
1989; 26 p
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Minato, Kazuo; Fukuda, Kousaku; Ikawa, Katsuichi
Japan Atomic Energy Research Inst., Tokyo1985
Japan Atomic Energy Research Inst., Tokyo1985
AbstractAbstract
[en] The composition of vapor and condensed phases at equilibrium and CVD phase diagrams were calculated for the CH3SiCl3-H2-Ar system using a computer code SOLGASMIX-PV, which is based on the free energy minimization method. These calculations showed that β-SiC, β-SiC+C(s), β-SiC+Si(s), β-SiC+Si(l), Si(s), Si(l), or C(s) would be deposited depending on deposition parameters. In the CH3SiCl3-Ar system, condensed phase was found to be β-SiC+C(s) or C(s). Comparing the calculated CVD phase diagrams with the experimental results from the literature, β-SiC+C(s) and β-SiC+Si(s) were deposited in the experiments at the high temperature (more than 2000K) and low temperature (less than 1700K) parts of a resion, respectively, where only β-SiC would be deposited in the calculations. These are remakable results to consider the deposition mechanism of silicon carbide. (author)
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Mar 1985; 33 p
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Report
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CARBIDES, CARBON COMPOUNDS, CHEMICAL COATING, COMPUTER CODES, DEPOSITION, DIAGRAMS, ENERGY, ENERGY SOURCES, FUELS, GAS COOLED REACTORS, GRAPHITE MODERATED REACTORS, INFORMATION, MATERIALS, NUCLEAR FUELS, PHYSICAL PROPERTIES, REACTOR MATERIALS, REACTORS, SILICON COMPOUNDS, SURFACE COATING, THERMODYNAMIC PROPERTIES
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AbstractAbstract
[en] The growth quality of YBaCuO thin films deposited by sputtering on different substrates (Al2O3, MgO, SrTiO3, Zr(Y)O2) has been studied by X-ray diffraction and channeling experiments as a function of the deposition temperature. Besides the substrate orientation, the substrate temperature is the parameter determining whether films grow in c-, a-, (110) or mixed directions. Epitaxial growth correlates with high critical current values in the films of up to 5.5x106 A/cm2 at 77 K. Ultrathin films with thicknesses down to 2 nm were grown revealing three-dimensional superconducting behaviour. Films on (100) SrTiO3 of 9 nm thickness and below are partially strained indicating commensurate growth. From the analysis of the surface disorder 1 displaced Ba atom per Ba2Y row was obtained indicating that the disordered layer thickness is about 0.6 nm. Tunnel junctions fabricated on these films reveal gap-like structures near ±16 mV and ±30 mV. (orig.)
[de]
Das Verfahren der Magnetron-Kathodenzerstaeubung wurde zur Abscheidung duenner YBaCuO-Schichten auf verschiedenen Substraten (Al2O3, MgO, SrTiO3, Zr(Y)O2) optimiert. Die Wachstumsrichtung und die kristalline Guete der Schichten wurde in Abhaengigkeit von der Substrat-Oberflaechenguete, der Orientierung und Temperatur mittels Ionenchanneling und Roentgendiffraktion untersucht. Der Grad der Epitaxie und die Mosaikverbreiterung bestimmen den kritischen Transportstrom mit Werten bis zu 5.5.106 A/cm2 bei 77 K. Selbst in ultraduennen Schichten mit einer minimalen Dicke von bis zu 2 nm zeigt das supraleitende Verhalten 3-dimensionalen Charakter. Schichten auf (100) SrTiO3 mit Dicken kleiner etwa 9 nm sind teilweise zur Unterlage verspannt, was auf kommensurables Wachstum hinweist. Die Channeling-Analyse der Schichtoberflaeche ergibt in guenstigen Faellen eine Verlagerung von nur 1 Ba-Atom pro Ba2Y-Kette, was einer maximalen Dicke der gestoerten Oberflaeche von etwa 0.6 nm entspricht. Auf diesen Schichten praeparierte Tunneldioden zeigen Strukturen mit einer Energieluecke in der Naehe von ±16mV und ±30mV. (orig.)Primary Subject
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Aug 1989; 99 p
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Oles, A.M.; Zaanen, J.
Abstracts of the European conference: Physics of magnetism'93. Strongly correlated electron systems1993
Abstracts of the European conference: Physics of magnetism'93. Strongly correlated electron systems1993
AbstractAbstract
[en] Short communication
Original Title
Containing lanthanum oxides
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Source
Uniwersytet Adama Mickiewicza, Poznan (Poland). Inst. Fizyki; Polska Akademia Nauk, Poznan (Poland). Inst. Fizyki Molekularnej; 243 p; ISBN 83-85481-50-8;
; 1993; p. 24; Osrodek Wydawnictw Naukowych; Poznan (Poland); Physics of Magnetism'93: Strongly Correlated Electron Systems. The European conference; Poznan (Poland); 21-24 Jun 1993; Available from Institute of Physics, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland

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AbstractAbstract
[en] We review some of the relevant physical properties of the transition metal mono-silicides with the FeSi structure (CrSi, MnSi, FeSi, CoSi, NiSi, etc.) and explore the relation between their structural characteristics and the electronic properties. We confirm the suggestion orginally made by Pauling that the FeSi structure supports two quasi-atomic d-states at the transition metal atom. This shell contains from 0 to 4 electrons in the sequence CrSi to NiSi. In FeSi the two quasi-atomic d-electrons are responsible for the high temperature S=1 state, which is compensated for T=0 by two itinerant electrons associated with the Fe-Si resonance bonds. (orig.)
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International conference on low energy electrodynamics in solids (LEES '97); Ascona (Switzerland); 6-11 Jul 1997; 28 refs.
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Journal Article
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BOND LENGTHS, CARRIER DENSITY, CHROMIUM SILICIDES, COMPARATIVE EVALUATIONS, CRYSTAL STRUCTURE, ELECTRONEGATIVITY, ELECTRONIC STRUCTURE, HALL EFFECT, INFRARED SPECTRA, IRON SILICIDES, KONDO EFFECT, MAGNETIC MOMENTS, MAGNETIC SUSCEPTIBILITY, MANGANESE SILICIDES, NICKEL SILICIDES, OSCILLATOR STRENGTHS, PERMITTIVITY, PHONONS, REVIEWS, SPACE GROUPS
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Koike, Y.; Adachi, T.; Sato, H.; Katano, S.
Progress report on neutron scattering research (April 1, 1996 - March 31, 1997)1997
Progress report on neutron scattering research (April 1, 1996 - March 31, 1997)1997
AbstractAbstract
No abstract available
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Ishii, Yoshinobu; Suzuki, Jun-ichi; Fujiwara, Satoru (eds.); Japan Atomic Energy Research Inst., Tokyo (Japan); 118 p; Oct 1997; p. 50
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Report
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ALKALINE EARTH METAL COMPOUNDS, BEAMS, CHALCOGENIDES, COHERENT SCATTERING, DIFFRACTION, ELECTRIC CONDUCTIVITY, ELECTRICAL PROPERTIES, LANTHANUM COMPOUNDS, NUCLEON BEAMS, OXIDES, OXYGEN COMPOUNDS, PARTICLE BEAMS, PHYSICAL PROPERTIES, RARE EARTH COMPOUNDS, SCATTERING, TEMPERATURE RANGE, TRANSITION ELEMENT COMPOUNDS
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