Oxygen diffusion in the superconducting oxide YBa sub 2 Cu sub 3 O sub 7 minus x

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.4549· OSTI ID:5650425

Xie, X M; Chen, T G; Wu, Z L ^[1]

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1. Shanghai Institute of Metallurgy, Academia Sinica, Shanghai, China 200050 (CN)

A low-frequency internal friction peak was observed at 200 {degree}C for sintered YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} bar specimens annealed at different temperatures between 400 and 650 {degree}C. This peak is interpreted in terms of diffusional jumps of oxygen atoms in the basal planes between sublattice sites O{sub A}(1/2, 0,0) and O{sub B}(0,1/2,0). These two sites are not crystallographically equivalent in orthorhombic symmetry. Oxygen diffusivity for planar diffusion in the basal planes was derived on the basis of a one-dimensional random-walk process, which yields: D = (1/4)d{sup 2}C{sub B}/(C{sub A} + C{sub B}){nu} {nu}{sub 0} exp ({minus}H{sub B}/kT) = D{sub 0} exp ({minus}H{sub B}/kT), where H{sub B} = H{sub A} + {Delta}E. The parameters C{sub A}, C{sub B}, {nu}{sub 0}, and H{sub A} are evaluated from internal friction data for the specimens of known oxygen deficiency x and {Delta}E, the potential energy difference between sites O{sub A} and O{sub B}, from Boltzmann's distribution law C{sub A}/C{sub B} = exp({minus}{Delta}E/kT). The preexponential factor D{sub 0} = 3.5 {times} 10{sup {minus}4} cm{sup 2}/sec and the activation energy of the 200{degree}C internal-friction peak H{sub A} = 1.03 eV are both temperature insensitive. By contrast, {Delta}E is temperature dependent; it is 0.23 eV at 400{degree}C and decreases as the temperature is raised, vanishing at 670{degree}C, the temperature of the orthorhombic-to-tetragonal transition temperature at which O{sub A} and O{sub B} sites become indistinguishable. Non-Arrhenius behavior exists between the oxygen diffusivity and the diffusion temperature in this type of diffusion mechanism.

• OSTI ID: 5650425
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:7; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
ATOM TRANSPORT
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DIFFUSION
ELEMENTS
FRICTION
HEAT TREATMENTS
INTERNAL FRICTION
MATERIALS
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
RADIATION TRANSPORT
SINTERED MATERIALS
STOICHIOMETRY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES