We have studied the local structure around Co in YBa2(Cu1−xCox)3O7−δ thin films with three different concentrations: x=0.07, 0.10, 0.17, and in a PrBa2(Cu1−xCox)3O7−δ thin film of concentration x=0.05 using the X-ray Absorption Fine Structure (XAFS) technique. Data were collected at the Co K-edge with polarizations both parallel and perpendicular to the film surface. We find that the oxygen neighbors are well ordered and shortened in comparison with YBCO Cu-O values to 1.80 \AA{} and 1.87 \AA{} in the c-axis and ab-plane, respectively. A comparison of further neighbors in the thin film and powder data show that these peaks in the film are suppressed in amplitude relative to the powder samples, which suggests there is more disorder and/or distortions of the Co environment present in the thin films.
@article{arxiv.cond-mat/9603104,
title = {Local structure study about Co in YBa$_2$(Cu$_{1-x}$Co$_x$)$_3$O$_{7-\delta}$ thin films using polarized XAFS},
author = {E. D. Bauer and F. Bridges and C. H. Booth and J. B. Boyce and T. Claeson and G. Brorsson and Y. Suzuki},
journal= {arXiv preprint arXiv:cond-mat/9603104},
year = {2009}
}