Preparation of High-T_c Bi-Sr-Ca-Cu-O Superconducting Thin Films by AC Sputtering

Abstract

Thin films of Bi-Sr-Ca-Cu-O superconductors were prepared on a polycrystalline YSZ substrate by the 50 Hz ac sputtering method. A pair of targets with various compositions were used in this apparatus. The films deposited without intentional heating were amorphous insulators. When the films were annealed at temperatures ranging from 750°C to 900°C, X-ray diffraction analysis showed that they had highly oriented periodic superstructures with various planar spacings. A specimen annealed at 800°C for 120 min has T c (onset) and T c (zero resistive) of 115 K and 73 K, respectively.