Large critical currents and improved epitaxy of laser ablated Ag-doped YBa2Cu3O7−δ thin films

Microstructure and critical current densities of laser ablated YBa2Cu3O7−δ thin films doped with 2–20 wt. % Ag have been studied. A critical current density as high as 1.4×107 A cm−2 at 77 K has been realized on 〈100〉 SrTiO3 substrates with YBaCuO films doped with 5 wt. % Ag which has been found to be the optimum. Evidence indicates that the improved microstructure and epitaxy which is a consequence of grain enlargement and alignment caused by Ag is responsible for the high values of critical currents observed.