engleski

Correlation between axial-oxygen anharmonicity and Tc in YBa2Cu3O7 and related compounds

Cu-O radial distribution functions in YBa/sub 2/Cu/sub 3/O/sub 7/, YBa/sub 2/Cu/sub 2/O/sub 6.5/ and YBa/sub 2/Cu/sub 2.8/Co/sub 0.2/O/sub 7+ delta / at 10 K have been determined from Cu K-edge polarized extended X-ray absorption fine structure of these materials, using model potentials to describe the effect of the Cu-O relative motion. The analysis shows that the axial oxygen atom moves in a double- well potential. A correlation between interwell tunneling and T/sub c/ is observed, and interpreted as a correlation between anharmonicity and T/sub c/.

high temperature superconductors ; transition temperature ; Cu K-edge polarized extended X-ray absorption fine structure

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