A NEW METHOD OF GROWING YBA2CU3OY 45-DEGREES BI-EPITAXIAL THIN-FILMS ON MGO SUBSTRATE

We have developed a new bi-epitaxial structure, namely YBCO/CeO2/YSZ/P rBCO/MgO and YBCO/CeO2/YSZ/MgO boundary to replace the original YBCO/C eO2/YSZ/MgO and YBCO/MgO boundary. The new structure has several advan tages. One is for the device fabrication consideration because the non -superconducting PrBCO thin films with brown color can be used as an e ndpoint detection for dry etching. The second one is to reduce the mis match between YBCO and MgO substrate. The third benefit is to get rid of a small amounts of 45 degrees orientation in YBCO/MgO, which might cause the junction to be shorted. X-ray phi scans are performed to cha racterize the epitaxial grouth and crystalline axis rotations. Critial currents of 2 mm wide junctions are measured.