1988 Volume 14 Issue 3-4 Pages 191-198
High T_c superconducting thin films of Ba-Y-Cu-O have been prepared on MgO (100) substrate using ion beam sputtering (IBS) method. After post-deposition oxygen annealing at 920〜940℃, the films exhibited sharp superconucting transitions with T_c endpoint of 79 K. Also annealed films consist of strongly preferred grains with the c-axis perpendicular to the plane of substrate. In this paper we studied the relationship between the superconducting properties and the annealing conditions whereas the latters had a great influence upon the nucleation and growth processes of the 1 2 3 phase. Quite a small amount of Mg diffused from substrates degrades the transition temperature of the annealed films by about 10 K lower than that of bulk ceramics superconductor.
