Role of elasticity associated with oxygen ordering in YBa{sub 2}Cu{sub 3}O{sub {ital z}}
- Department of Materials Science & Mineral Engineering, and Materials Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
- Department of Physics, Florida Atlantic University, Boca Raton, Florida 33431 (United States)
A Monte Carlo technique incorporating elasticity is applied to simulate oxygen-vacancy ordering and concomitant elastic distortion within the basal plane of YBa{sub 2}Cu{sub 3}O{sub {ital z}}. The simulation model employs an extension of an anisotropic Ising model to account for small displacements of copper, oxygen, and vacancy positions within the basal plane so that the simultaneous evolution of atomic positions and occupancies can be examined. Simulations performed with this model are first compared to previous studies of oxygen-vacancy ordering under a static lattice approximation, and then used to investigate the contribution of elastic strain to the formation of experimentally observed {radical}2 superstructures, deformation tweed, twinning, nucleation and growth of ordered domains, and the nature of the tetragonal-to-orthorhombic transition occurring in this system. The influence of elasticity on microstructural evolution is examined via simulations of rapid quenching through the tetragonal-to-orthorhombic transition or of deformation of the orthorhombic phase to induce strain, both followed by annealing. Results are presented as lattice configuration photographs, fast Fourier transform intensity distributions, and strain maps. The formation and evolution of these microstructures are rationalized in terms of the accommodation of strain energy accumulated during the course of the simulated thermomechanical treatments. The formation of the {radical}2 {ital a}{sub 0}{times} {radical}2 {ital a}{sub 0} structure is found to result from strain dissipation via a softened phonon mode with wave vector {bold q}=[1/21/20].
- Research Organization:
- Lawrence Berkeley National Laboratory
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 76456
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 2 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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