Structural transformations in nonstoichiometric YBa sub 2 Cu sub 3 O sub 6+. delta

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.6511· OSTI ID:7018714

Semenovskaya, S; Khachaturyan, A G ^[1]

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1. Department of Materials Science and Engineering, Rutgers University, P.O. Box 909, Piscataway, New Jersey 08855-0909 (United States)

Structural-transformation kinetics in YBa{sub 2}Cu{sub 3}O{sub 6+{delta}} caused by oxygen ordering is considered. The effect of long-range interaction between oxygen atoms, Coulomb repulsion, and strain-induced interaction on oxygen ordering is investigated in terms of crystal-lattice-site diffusion theory. Computer simulations of the diffusion of interacting O atoms give a complicated sequence of atomic-scale and mesoscale structural transformations. It is shown that the transformation path strongly influences the crystallographic structure of the ordered phases. An interrelation between the mesoscale and the atomic structures, which proves to be coupled by the long-range interaction, is found. The following structures are obtained: the primary tweed which transforms into a (110) polytwin structure, the secondary tweed, and the glassy'' state, as well as 2{ital a}{sub 0}{times}2{ital a}{sub 0} and 2 {radical}2 {ital a}{sub 0}{times}2 {radical}2 {ital a}{sub 0} superstructures. Two structural states, the secondary tweed and the glassy'' state, are shown to be mesoscopic phases---metastable (or stable) phases whose phase identity is mostly determined by their mesoscale rather than atomic-scale structure. The structures and morphologies generated in this computer simulation were reported in many experimental studies.

• DOE Contract Number: FG05-90ER45430
• OSTI ID: 7018714
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:10; ISSN PRBMD; ISSN 0163-1829
• 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
COMPUTERIZED SIMULATION
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
HIGH-TC SUPERCONDUCTORS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SIMULATION
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES