X-Ray Absorption Spectra of High Tc Superconducting SrxLa2-xCuO4-y

Abstract

Cu K-edge extended X-ray absorption fine structure (EXAFS) and near-edge structure have been measured in high T _c superconducting Sr _x La_2-x CuO_4-y . The Fourir transform analysis shows the axial elongation of CuO₆ octahedron along the c-axis with four short (1.89 Å) and two long (2.41 Å) Cu-O bonds, which are slightly shorter than those in CuO and La₂CuO₄ indicating the presence of enhanced Cu(3d)-O(2p) interaction. The near-edge spectrum of Sr _x La_2-x CuO_4-y is similar to that of Cu₂O rather than CuO, which is interpreted as an evidence for the monovalent character of Cu ions.