IN-SITU DEPOSITION OF YBCO THIN-FILMS BY SPUTTERING UNDER LOW-OXYGEN PARTIAL-PRESSURE

Y-Ba-Cu-O superconducting thin film was grown on the SrTiO3 substrate by in situ 90-degrees-off-axis rf magnetron sputtering under the low o xygen partial pressure of 0.67 Pa (5 mTorr) from different targets wit h various Ba/Y ratios. All films were grown at 645-degrees-C with thei r c-axis normal to the substrate surface. The critical temperature and c-axis length approached the optimum values as the Ba/Y ratio of the target decreased from 2 to 1. In addition, the effect of the oxygen pr essure during cooling after deposition on the critical temperature and the c-axis length of the thin films was determined.