Superconducting thin films of BiSrCaCuO made by sequential electron beam evaporation

This is the authors' abstract. We don't add key points for this paper.

Superconducting thin films of Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub x/ have been made by sequential electron-beam evaporation of multiple layers of Bi and Cu metals and (Sr,Ca)F/sub 2/ on MgO substrates. The films were annealed at high temperature, first in wet O/sub 2/ and then in dry O/sub 2/, and cooled to room temperature in dry O/sub 2/. The resulting films, which are approximately 1 mu m thick, have transition temperatures of approximately 85 K. X-ray diffraction shows that the films are preferentially oriented with their c-axis perpendicular to the MgO substrate. The best film has a zero-resistance temperature of 90 K and critical-current densities of 8*10/sup 4/ A/cm/sup 2/ at 77 K and 2.5*10/sup 5/ A/cm/sup 2/ at 4.2 K.>