POLARIZATION-DEPENDENT EXAFS STUDY ON SUPERCONDUCTING YBA2CU3O7-DELTATHIN-FILM

The temperature dependence of polarization-dependent EXAFS of a superc onducting YBa2Cu3O7-delta thin film has been studied. The measurements were done on the Cu K-edge in the fluorescent mode over the temperatu re range 30-300K with the ab plane and the c axis parallel to the X-ra y polarization vector, epsilon. The results indicate that the the valu es of mean square relative displacement sigma(2) of the nearest neighb or Cu-O pairs increase near Tc in the axial Cu-O bonds.