Oxygen disorder and the structures of high-T/sub c/ superconductors by neutron powder diffraction

Journal Article · Mon May 01 04:00:00 EDT 1989 · IBM Journal of Research and Development; (USA)

DOI:https://doi.org/10.1147/rd.333.0220· OSTI ID:5731478

Hewat, A W ^[1]; Hewat, E A; Bordet, P; Capponi, J J; Chaillout, C; Chenavas, J; Hodeau, J L; Marezio, M; Strobel, P ^[2]; Francois, M ^[3]

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1. Institute Max von Laue-Paul Langevin, 156X, 8042 Grenoble Cedex (FR)
2. CNRS Laboratoire de Cristallographie 155X, 38041 Grenoble Cedex (FR)
3. Laboratoire de Cristallographie, Universite de Genieve, CH-1211, Geneve (CH)

All of the high-T/sub c/ perovskite superconductors appear to show disorder of certain oxygen atoms. In (La,Sr)/sub 2/CuO/sub 4/ and perhaps also in YBa/sub 2/Cu/sub 3/O/sub 7/ this is associated with a structural transition. The Bi and Tl superconductors, for which the authors have neutron structural data on four different phases, also how oxygen disorder which may be associated with valence fluctuations. In Tl/sub 2/Ba/sub 2/CuO/sub 6/, electron holes are created by the absence of 1/8 of the atoms in the TlO plane, producing a marked superstructure. However, this material is not superconducting if the superstructure is well ordered, with an orthorhombic (strictly monoclinic) structure. The T/sub c/ appears to depend on the disorder of the superstructure to produce a pseudotetragonal metric in which the oxygen atoms within the TlO plane are distributed over four equivalent sites about the center of the Tl square.

• OSTI ID: 5731478
• Journal Information: IBM Journal of Research and Development; (USA), Journal Name: IBM Journal of Research and Development; (USA) Vol. 33:3; ISSN IBMJA; ISSN 0018-8646
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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& Refractories-- Structure & Phase Studies
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Cermets
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101* -- Activation
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Radiometric & Radiochemical Procedures
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ATOMS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
ELECTRON-HOLE COUPLING
ELEMENTS
HIGH TEMPERATURE
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
NEUTRON DIFFRACTION
NONMETALS
ORDER-DISORDER TRANSFORMATIONS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PEROVSKITES
PHASE TRANSFORMATIONS
POWDERS
RARE EARTH COMPOUNDS
SCATTERING
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES