High-temperature superconductivity in YBa/sub 2/Cu/sub 3/O/sub 7/ and related perovskite oxides: Some aspects of solid state chemistry

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · Mater. Res. Bull.; (United States)

DOI:https://doi.org/10.1016/0025-5408(87)90040-7· OSTI ID:6294412

Rao, C N.R.; Ganguly, P; Sreedhar, K; Ram, R A.M.; Sarode, P R

Thermogravimetry and Cu K-absorption edge measurements show that the superconducting YBa/sub 2/Cu/sub 3/O/sub 7/ sample (annealed in O/sub 2/) contains more oxygen than the nonsuperconducting sample annealed in N/sub 2/, the former has a less distorted structure with the actual composition not far from the ideal one. Oxides of the formula Y/sub 1-x/Ba/sub 2/Cu/sub 3/O/sub 7/ (x = 0.05, 0.10 and 0.15) annealed in oxygen also possess the perovskite structure and show high-T/sub c/ superconductivity. The superconducting transition temperature seems to generally increase with the nominal Cu/sup 3+//Cu/sup 2+/ ratio in the superconducting copper oxides. Control of the Cu/sup 3+//Cu/sup 2+/ ratio (and hence the density of states at the metal-nonmetal transition in the non-superconducting state) through the oxygen stoichiometry or an appropriate cation substitution seems to provide a basis for synthesizing high-T/sub c/ copper oxides.

• Research Organization: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012
• OSTI ID: 6294412
• Journal Information: Mater. Res. Bull.; (United States), Vol. 22:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
SUPERCONDUCTIVITY
TRANSITION TEMPERATURE
COPPER OXIDES
YTTRIUM OXIDES
ANNEALING
COMPARATIVE EVALUATIONS
DENSITY
ION EXCHANGE
K ABSORPTION
NITROGEN
OXYGEN
PEROVSKITES
SAMPLING
STOICHIOMETRY
STRUCTURAL CHEMICAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
ABSORPTION
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
COPPER COMPOUNDS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
GRAVIMETRIC ANALYSIS
HEAT TREATMENTS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
SYNTHESIS
THERMAL ANALYSIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360603 - Materials- Properties
360602 - Other Materials- Structure & Phase Studies