Influence of substrate temperature on epitaxial growth of YBa2Cu3O6.9 superconducting films under laser sputtering

Using ac resistivity measurements, X-ray diffraction and Auger spectroscopy we have investigated the influence of SrTiO3 substrate temperature (Ts) on the epitaxial growth of superconducting YBaCu3O6.9 films evaporated by a moderate energy (∼< 0.05 joules per pulse) laser beam. A specially devised evaporation chamber enabled us to evaporate high Tc films and to investigate their surface properties (Auger spectra) in situ. The Y-Ba-Cu-O thin films were evaporated from a rotated cyylindrical target of YBa2Cu3O6.9 superconducting ceramic onto a SrTiO3 (100) single crystal substrate which also has been rotated.The films were subsequently annealed for one hour at different temperatures in an O2 flow in the same chamber immediatly after evaporation and cooled down slowly (100 deg C/hour) to room temperature