Structural phase transitions and oxygen-oxygen interaction energies in YBa sub 2 Cu sub 3 O sub 6+ x

Journal Article · Wed Jul 01 00:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.381· OSTI ID:5002631

Hilton, D K; Gorman, B M ^[1]; Rikvold, P A ^[2]; Novotny, M A ^[3]

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1. Department of Physics B-159 and Center for Materials Research Technology B-159, Florida State University, Tallahassee, Florida 32306-3016 (United States) Supercomputer Computations Research Institute B-186, Florida State University, Tallahassee, Florida 32306-4052 (United States)
2. Department of Physics B-159 and Center for Materials Research Technology B-159, Florida State University, Tallahassee, Florida 32306-3016 (United States) Supercomputer Computations Research Institute B-186, Florida State University, Tallahassee, Florida 32306-4052 (United States) Tohwa Institute for Science, Tohwa University, Fukuoka 815 (Japan) Department of Physics, Kyushu University 33, Fukuoka 812 (Japan)
3. Supercomputer Computations Research Institute B-186, Florida State University, Tallahassee, Florida 32306-4052 (United States)

We investigate the effects of varying the interaction constants in a lattice-gas model for oxygen ordering in the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}}. A detailed ground-state calculation yields seven topologically distinct ground-state diagrams, which are realized for different values of the interactions. For interactions that produce the experimentally observed ordered phases, we present transfer-matrix finite-size scaling (TMFSS) results which, together with the gound-state diagram, can be used to approximate the global shape of the finite-temperature phase diagram. The effective oxygen-oxygen interactions in YBa{sub 2}Cu {sub 3}O{sub 6+{ital x}} are estimated by a nonlinear least-squares fit to newly available experimental data of the numerical lattice-gas phase diagram obtained by the TMFSS method with strip widths 8 and 12. An interesting feature of the fitted phase diagram is that a narrow region of the ortho-1/2 phase is found to extend between the tetragonal and ortho-1/4 phases at low oxygen concentration. The fitted interactions and the resulting phase diagram are compared with those recently obtained by Sterne and Wille, using the linear muffin-tin orbital method. We find the reasonable agreement achieved between the effective interactions predicted by these two fundamentally different methods highly encouraging.

• DOE Contract Number: FC05-85ER25000
• OSTI ID: 5002631
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:1; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
DIAGRAMS
ENERGY LEVELS
GROUND STATES
HIGH-TC SUPERCONDUCTORS
INTERACTIONS
IONS
MATHEMATICS
NUMERICAL ANALYSIS
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
SUPERCONDUCTORS
TRANSFER MATRIX METHOD
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES