Formation of High‐Tc 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 Tc(onset)= 120 K and Tc(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 Tc(zero). The films show preferred orientation and adhere well to the substrate.