Twin and tweed microstructures in YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] doped by trivalent cations

Journal Article · Sat May 01 00:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.47.12182· OSTI ID:6677458

Semenovskaya, S ^[1]; Zhu, Y; Suenaga, M ^[2]; Khachaturyan, A G ^[1]

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1. Department of Materials Science, Rutgers University, P.O. Box 909, Piscataway, New Jersey 08855-0909 (United States)
2. Division of Materials Science, Brookhaven National Laboratory, Upton, New York 11973 (United States)

Computer-simulation techniques and TEM analysis were employed to study the dependence of the twin and tweed microstructures in YBa[sub 2]Cu[sub 3[minus][ital x]]M[sub [ital x]]O[sub 7[minus][delta]] on doping by trivalent atoms (like Fe, Co, or Al). Since the trivalent atoms substituting the bivalent Cu(I) atoms have a greater number of the nearest-neighbor oxygen atoms, it was suggested that doping can be described by the [ital M]-O nearest-neighbor attractive interaction. This interaction generates a local oxygen disorder which plays an important role in the formation of the tweed structure. The [ital M]-O interaction and the long-range O-O interaction (screened Coulomb and strain induced) were taken into account to simulate the oxygen ordering kinetics. The simulation is based on equations describing the microscopic diffusion of oxygen atoms. The obtained simulated microstructures are in qualitative and even quantitative agreement with electron microscopic observations for YBa[sub 2]Cu[sub 3[minus][ital x]]Fe[sub [ital x]]O[sub 7[minus][delta]] and with previous electron microscopic data. Both the computer simulations and the TEM results have shown that the usual twin structure, formed through coarsening and refining of the transient tweed structure, is produced at small doping ([ital x][le][similar to]0.08). At larger [ital x]([similar to]0.08[lt][ital x][lt][similar to]0.2--0.3), the dopant atoms prevent coarsening and a metastable (or stable) mesoscopic tweed pattern appears. Although the crystal lattice is locally distorted by ultrafine orthorhombic domains forming the tweed pattern, the average crystal lattice determining the diffraction spot pattern is tetragonal. At higher [ital x], the ultrafine orthorhombic domains producing the tweed structure disappear and a disordered tetragonal phase is formed.

• DOE Contract Number: FG05-90ER45430; AC02-76CH00016
• OSTI ID: 6677458
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 47:18; ISSN PRBMDO; 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
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COBALT ADDITIONS
COBALT ALLOYS
COMPUTERIZED SIMULATION
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
HIGH-TC SUPERCONDUCTORS
IRON ADDITIONS
IRON ALLOYS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
SIMULATION
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TWINNING
YTTRIUM COMPOUNDS
YTTRIUM OXIDES