As-grown superconducting Bi(-Pb)-Sr-Ca-Cu-O films by electron cyclotron resonance plasma sputtering

Abstract

Bi(‐Pb)‐Sr‐Ca‐Cu‐O thin films were prepared on MgO(100) single‐crystal substrates by electron cyclotron resonance (ECR) plasma sputtering at substrate temperatures from room temperature to 590 °C. Pb‐doped superconducting as‐grown films were obtained above 560 °C. The T_c values of the Pb‐doped films prepared at 570–590 °C were 58–64 K which increased with increasing substrate temperature. Pb‐undoped as‐grown films obtained at 590 °C showed superconduction (T_c =30 K), but the films obtained below 580 °C were semiconductors. The grain sizes and contents of the 37 Å phase (110 K phase) were increased by the Pb doping into the as‐grown Bi‐Sr‐Ca‐Cu‐O films.