Comparative study of superconducting LaBa/sub 2/Cu/sub 3/O/sub 7-delta/ and La/sub 3-x/Ba/sub 3+x/Cu/sub 6/O/sup 14+delta/*

Journal Article · Fri Apr 01 00:00:00 EST 1988 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(88)90154-5· OSTI ID:7007100

Ganapathi, L; Ganguli, A K; Mohan Ram, R A; Rao, C N.R.

Based on X-ray diffraction and electron microscopy it is shown that oxides of the general formula LaBa/sub 2/Cu/sub 3/O/sub 7-delta/ become tetragonal when delta deviates slightly from 0. This tetragonal structure is similar to that of La/sub 3-x/Ba/sub 3+x/Cu/sub 6/O/sub 14+delta/, with a cubic perovskite subcell and triple periodicity. Electron micrographs of these tetragonal oxides show 90/sup 0/ microdomains. Orthorhombic LaBa/sub 2/Cu/sub 3/O/sub 7-delta/ with high T/sub c/ (approx. 77 K) is found only when delta approx. = 0; this sample is subject to formation of twins. Fluorine substitution seems to favor superconductivity.

• Research Organization: Indian Institute of Science, Bangalore (India)
• OSTI ID: 7007100
• Journal Information: J. Solid State Chem.; (United States), Vol. 73:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRYSTAL STRUCTURE
PHASE STUDIES
SUPERCONDUCTIVITY
COPPER OXIDES
LANTHANUM OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
ORTHORHOMBIC LATTICES
TETRAGONAL LATTICES
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
CRYSTAL LATTICES
DATA
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INFORMATION
LANTHANUM COMPOUNDS
MICROSCOPY
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties