Superconducting Thin Films of Bi-Pb-Sr-Ca-Cu-O by dc Magnetron Sputtering from a Single Target

Superconducting thin films of the Bi-Pb-Sr-Ca-Cu-O system have been prepared on MgO substrates by dc magnetron sputtering from a single sintered target followed by post annealing, in order to examine the effect of Pb addition. The films deposited below 600°C are always amorphous and insulating. These films crystallize by high-temperature annealing in air and become superconducting with an onset temperature of 120 K. Zero resistivity at 107 K appears when the films are deposited at 400°C and post-annealed at 850°C for 15 h. Although the superconducting properties of the films were quite sensitive to the temperature and duration of the high-temperature annealing step, the growth of the high- T c phase in the films is clearly promoted by the addition of Pb.