Growth mode and microstructure of Ag-doped YBa2Cu3O7-δ thin films prepared by dual beam pulsed-laser deposition

Abstract

Ag-doped c-axis YBa2Cu3O7-δ thin films were fabricated by using dual-beam pulsed-laser deposition. When a small amount of silver was doped in the film grown at 700°C, the Jc value was obviously enhanced. The temperature dependence of Jc was found proportional to (1-T/Tc0)3/2 at T close to Tc0. In the films grown at 730°C, we observed long bar-like structures with lengths in tens of μm, oriented along or at 45° to the a/b axes of the film. The bars consisted mainly a-axis YBCO grains and a mixture of polycrystalline and amorphous oxides. Defects on substrate surface and growth temperature were found dominating in formation of the bars, which could be attributed to a Ag-assisted diffusion mechanism during the deposition process.