Formation of High‐T c Superconducting Bi‐Pb‐Sr‐Ca‐Cu Oxide Films by Spray Pyrolysis of an Oxalate Suspension

A Bi‐Pb‐Sr‐Ca‐Cu oxide superconducting thick film, exhibiting T c(onset) = 120 K and T c(zero) = 100 K, can be obtained by spray pyrolysis of oxalate suspension on the (100) MgO substrate, using the partial‐melting state at 860°C for 15 h, a rapid‐quenching process to 500°C, and a postannealing treatment for 1 h at 835°C. These processes are believed to enhance the volume fraction of 2223 phase and increase the T c(zero) . The films show preferred orientation and adhere well to the substrate.