MICROWAVE AND MICROSTRUCTURAL STUDIES OF SILVER-DOPED YBA2CU3O7-DELTATHIN-FILMS

Using the sapphire dielectric resonator method, we investigated the ef fect of silver on the microwave properties of high-temperature superco nducting 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 th e doping level increased from 2 wt% to 10 wt%, which showed a correlat ion with improved microstructure of films.