The distribution of Ag in Ag-doped YBa2Cu3O7-delta thin film prepared by dual-beam pulsed-laser deposition

The Ag distribution in Ag-doped YBa2Cu3O7-delta (YBCO) thin films fabricate d by dual-beam pulsed-laser deposition on SrTiO3 (100) substrates has been studied by Auger electron spectroscopy, microproton-induced x-ray emission, atomic force microscopy and scanning electron microscopy. All the results consistently show that Ag aggregated in the bar-like structures observed in the film. These bars are aligned along the a-b-axis or at 45 degrees to th e a-b-axis of the YBCO thin film. The main body of the long bars aligned wi th the a-b-axes of the Nm was found to be a combination of metallic Ag with other precipitates of YBCO film that may grow from the substrate surface t o the YBCO him surface. There were other precipitates aggregating as well a t the surface of these bars, such as oxides of Cu and Ba. The short bars th at aligned along 45 degrees to the a-b-axes of the film were found to be de ficient in Ag but rich in Cu, Ba and O, which could be oxide precipitates o f YBCO. The growth mechanisms of the two types of bars seem quite different .