Oxidation thermodynamics of YBa sub 2 Cu sub 3 O sub 6+ y : Evidence for the presence of localized oxygen p holes

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.4302· OSTI ID:7143513

Verweij, H; Feiner, L F ^[1]

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1. Philips Research Laboratories, P.O. Box 80.000, 5600 JA Eindhoven, The Netherlands (NL)

An analysis is presented of the high-temperature thermodynamic data of the oxidation reaction of YBa{sub 2}Cu{sub 3}O{sub 6+{ital y}} in the orthorhombic phase ({ital y}{approx gt}0.6). From the independence of the reaction enthalpy on temperature and oxygen content we argue that a localized ionic picture is appropriate. We then analyze a series of models, assuming that the vacancy-oxygen occupation of chain sites is random along the {ital b} axis, and that the charge compensation associated with oxygen take-up occurs by oxidation of Cu{sup +} in the CuO{sub {ital y}} chain fragments {ital and} by creation of holes on oxygen ions. The results demonstrate that in the chains the oxygen ions determine the valency of the neighboring Cu ions. Most importantly, the agreement obtained with the experimental data provides evidence for the presence of localized {ital p} holes; the bandwidth of any hole band is estimated to be less than 0.1 eV. The results further indicate that if oxygen {ital p} holes are present both in the chains and in the CuO{sub 2} planes, the holes in the chains have their spins coupled to the Cu spins, while the holes in the CuO{sub 2} planes go into bound states centered on copper sites by forming a singlet with the Cu{sup 2+}({ital d}{sup 9}) spin.

• OSTI ID: 7143513
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRONIC STRUCTURE
ENTHALPY
HOLES
IONS
ORTHORHOMBIC LATTICES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PHYSICAL PROPERTIES
POINT DEFECTS
STRUCTURAL MODELS
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENT COMPOUNDS
VACANCIES
YTTRIUM COMPOUNDS
YTTRIUM OXIDES