GRAIN-BOUNDARY JUNCTIONS WITH AG-DOPED YBA2CU3O7-X EPITAXIAL THIN-FILMS

Using a de sputtering method at high oxygen pressures we have deposite d epitaxial Ag-doped YBa2Cu3O7-x thin films on SrTiO3 bicrystals with missorientation angle of 36.8 degrees. A 15 % Ag-doped YBa2Cu3O7-x sin tered target was used to sputter the films. Critical current of 4-5 10 (6) A/cm(2) at 77 K were measured in doped films. When compared with 1 x10(6) A/cm(2) for undoped films, indicates an improvement of the supe rconducting properties by Ag doping. 200- 300 nm thick Ag-doped films were patterned across the bicrystal line to form 5-20 mu m-wide juncti ons. Current-voltage characteristics of the grain boundary junctions a t temperatures from 10 K to T-C showed a resistively shunted junction (RSJ) behavior with ICRN values of 160-170 mu V at 77 K which are high er than the measured values for undoped junctions.