Microwave and microstructural studies of silver-doped YBa2Cu3O7-δ thin films

Using the sapphire dielectric resonator method, we investigated the effect of silver on the microwave properties of high-temperature superconducting YBa2Cu3O7-delta (YBCO) thin films on MgO substrates at 25 GHz. Silver-doped YBCO films were prepared by laser ablation from targets of Ag doping of 2, 6, 8 and 10 wt%, and their crystal structures were characterized by x-ray diffraction and scanning electron microscopy. The surface resistance of Ag-doped YBCO films decreased by 20% when the doping level increased from 2 wt% to 10 wt%, which showed a correlation with improved microstructure of films.