80 K superconductivity in Bi-Sr-Cu-O thin films

High- T c superconductivity near 80 K has been obtained in Bi-Sr-Cu-O thin films. Films were prepared by rf-magnetron sputtering onto heated MgO substrates and heat-treated. It was found that the Bi-based crystal structure with a c -axis length of 3.12 nm was formed in thin film. This film exhibited the superconducting transition with the onset temperature of about 80 K. The present superconducting phase in the Bi-Sr-Cu-O system is considered to be the isostructure with the conventional 80 K Bi 2 Sr 2 CaCu 2 O y (2-2-1-2) phase.