1 November 1991 Polarization-dependent x-ray spectroscopy of high-Tc superconductors
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For anisotropic structures such as those found for the high Tc superconductors, the utility of x-ray absorption measurements can be enhanced by taking advantage of the inherent polarization of synchrotron radiation. Polarization dependent measurements have been made on all four classes of high Tc materials (La, Y, Bi, and Tl based Cu oxides) after orienting them magnetically. All show similar polarization dependence for their near edge structure which is characteristic of planar Cu compounds. The paper concentrates on results for YBa2Cu3O7-x materials. The two types of Cu sites in this material have different polarization dependence, and measurements with the x-ray polarization parallel and perpendicular to the c-axis can be used to distinguish their contributions to the near edge structure. We can clearly resolve the 4p(pi) contributions from the two sites. The extended fine structure also shows distinct polarization dependence which allows the separation of contributions from in-plane and out-of-plane bonds. Measurements on oxygen deficient materials show contributions from Cu1+ which is determined to be on the Cu(1) (linear chain) sites from the polarization dependence, and to vary linearly with the O concentration.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Steve M. Heald, Steve M. Heald, John M. Tranquada, John M. Tranquada, } "Polarization-dependent x-ray spectroscopy of high-Tc superconductors", Proc. SPIE 1550, X Rays in Materials Analysis II: Novel Applications and Recent Developments, (1 November 1991); doi: 10.1117/12.49468; https://doi.org/10.1117/12.49468

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