Numerical investigation of a model for oxygen ordering in YBa sub 2 Cu sub 3 O sub 6+ x
- IBM Bergen Scientific Centre, Thormohlensgate 55, Bergen High Technology Centre, N-5008 Bergen, Norway (NO)
- Supercomputer Computations Research Institute B-186, Florida State University, Tallahassee, Florida 32306-4052 (USA)
- Department of Physics B-159, Florida State University, Tallahassee, FL (USA) Center for Materials Research and Technology B-159, Florida State University, Tallahassee, FL (USA) Supercomputer Computations Research Institute B-186, Florida State University, Tallahassee, Florida 32306-3016
- Department of Physics and Astronomy, University of Georgia, Athens, GA (USA) Center for Simulational Physics, University of Georgia, Athens, Georgia 30602 (USA)
We report the results of large-scale Monte Carlo and transfer-matrix studies of a model lattice-gas Hamiltonian that has previously been introduced to stidy the oxygen ordering responsible for the orthorhombic-to-tetragonal transition in YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}}. We analyze the data using finite-size scaling to obtain the phase diagram and critical exponents. At high temperatures we find qualitative agreement with the cluster-variation method. However, at low temperatures we find only second-order transitions, in disagreement with the cluster-variation method. The critical exponents found are consistent with the universality classes of the {ital d}=2 Ising model and the {ital XY} model with cubic anisotropy. Consequently, any experimental evidence of a first-order transition for YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} would imply that the model of Wille, Berera, and de Fontaine (Phys. Rev. Lett. 60, 1065 (1988)) needs to be modified to be directly applicable to this material.
- DOE Contract Number:
- FC05-85ER25000
- OSTI ID:
- 6974760
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:13; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL MODELS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIAGRAMS
HAMILTONIANS
ISING MODEL
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
MONTE CARLO METHOD
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
QUANTUM OPERATORS
SCALING LAWS
SUPERCONDUCTORS
TETRAGONAL LATTICES
TRANSFER MATRIX METHOD
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES