Evidence of local structural transition during oxidation process of RBCO epitaxial lms using time resolved reflexafs measurements

We report results of a time resolved X-ray Absorption Spectroscopy (XAS) experiment on the oxidation process of epitaxial Y1(Nd0:05Ba1:95)Cu3Ox superconducting thin lms. For the rst time Cu K-edge XAS technique has been used to explore local structural changes around the Cu ions during the oxidation process of a high critical temperature superconducting lm. The results show that during the oxygenation of a tetragonal Y1(Nd0:05Ba1:95)Cu3Ox additional local transitions appear in the orthorhombic I phase, which are not linked to long range order transformations as shown by in situ X-ray diraction experiment. New questions concerning the dynamic microscopic process leading to the oxygenation and eventually to superconductivity of the complex R1+xBa2-xCu3Ox (R = Y or rare earth) compounds arose from these results.