NONHOMOGENEITY OF THE CUO2 PLANE OF THE OXYGEN DOPED LA2CUO4.1 SYSTEMBY POLARIZED EXAFS

Temperature dependent in-plane polarized Cu K-edge extended x-ray abso rption fine structure (EXAFS) study has been carried out on a high qua lity single crystal of oxygen doped La2CuO4.1 (LCO) system to investig ate the local structure around Cu. The EXAFS data recorded with high d egree of plane polarization and up to high momentum transfer (Q=40 A(- 1) = 2k) allowed the quantitative determination of the distorted and u ndistorted Cu planes. The determination of the Cu-O(planar) distances shows presence of minority Cu sites characterized by two longer Cu-O(p lanar) bonds and a tilting of 15 degrees with the average crystallogra phic structure at T < T-s similar to 150 K. The data show the coexiste nce of localized and itinerant charges trapped into stripes of distort ed and undistorted domains within the CuO2 plane.