Oxygen-vacancy phase equilibria in YBa/sub 2/Cu/sub 3/O/sub z/ calculated by the cluster variation method
Ordering in the Cu-O basal plane of YBa/sub 2/Cu/sub 3/O/sub x/ is investigated as a function of oxygen content, chemical potential, and temperature. Two-phase diagrams are calculated by means of the cluster variation method applied to asymmetric two-dimensional Ising models with one nearest-neighbor and two second-nearest-neighbor interactions. The interaction parameters selected ensure the stability of the orthorhombic structures near z = 7 and for one of the cases also includes a cell-doubling phase at z = 6.5. Oxygen pair and point probabilities are studied as a function of temperature under conditions of constant oxygen partial pressure. Comparison of site occupancy and orthorhombic-to-tetragonal second-order transition temperatures with recent experimental data are in excellent agreement.
- Research Organization:
- Department of Materials Science and Mineral Engineering and Department of Physics, University of California, Berkeley, California 94720
- OSTI ID:
- 6317296
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 39:10
- Country of Publication:
- United States
- Language:
- English
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Vacancy ordering in the basal plane of YBa/sub 2/Cu/sub 3/O/sub z/
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Related Subjects
BARIUM OXIDES
PHASE STUDIES
VACANCIES
COPPER OXIDES
YTTRIUM OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
ISING MODEL
ORTHORHOMBIC LATTICES
OXYGEN
PAIRING INTERACTIONS
PHASE DIAGRAMS
TEMPERATURE DEPENDENCE
TETRAGONAL LATTICES
VARIATIONAL METHODS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL MODELS
CRYSTAL STRUCTURE
DIAGRAMS
ELEMENTS
INTERACTIONS
MATHEMATICAL MODELS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POINT DEFECTS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties