Bi-Sr-Ca-Cu-oxide superconducting thin films deposited by dc magnetron sputtering

Thin films of the high-temperature superconductor Bi-Sr-Ca-Cu-oxide were deposited by dc magnetron sputtering onto various substrates. Films deposited on (100) MgO substrates achieved zero resistance between 78 and 82.5 K depending upon the annealing conditions. The best films were produced with a quick post-anneal in oxygen at 870 0C followed by a slower anneal in air at the same temperature. The composition of the sputtered films was uniform within +- 3% over an area 40 mm in radius, and films deposited at 15 and 40 mm from the center of deposition both exhibited high T/sub c/ transitions