Abstract
Bi-Pb-Sr-Ca-Cu-O superconductive films (Tc≥100K) were obtained by annealing films A((Bi+Pb)1.47Sr1.00Ca0.92Cu1.80Ox) at 850°C which were prepared by rf-magnetron sputtering using multi-targets. The critical current density (Jc) of the annealed films was greatly influenced by the surface roughness of the film. Jc increased proportionally with a decrease in surface roughness, indicating that the decrease of Jc was caused by the rough surface of the film, and by a liquid phase formed during the annealing process. To avoid the formation of the liquid phase and to obtain smooth surface films, low Ca content films B((Bi+Pb)1.27Sr1.00Ca0.76Cu1.37Ox) were prepared and annealed at a low temperature (835°C). The surface of the annealed film B was smoother than that of the annealed film A. The obtained films with smooth surface films showed high Jc(=27, 000A/cm2) at 77K in zero magnetic field.
