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

Ag-doped c-axis YBa2Cu3O7-delta 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 degreesC, the J(c) value was obviously enhanced. The temperature dependence of J(c) was found proportional to (1-T/T-c0)(3/2) at T close to T-c0. In the films grown at 730 degreesC, we observed long bar-like structures with lengths in tens of mum, oriented along or at 45 degrees 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.