Cross-Sectional Transmission Electron Microscope Studies of Multilayered Bi-Sr-Ca-Cu-O Films

Structures of the as-deposited and annealed Bi-O/Sr-Ca-Cu-O multilayered films with a designed period of 2.16 nm have been examined by a cross sectional TEM method. Although the as-deposited film is not superconducting, a clear Bi-O double layer/perovskite sandwich structure with a period of mostly 2.16 nm is observed. For the film annealed at 810°C, which is superconducting, a well defined modulated structure similar to that of the bulk-BSCCO is constructed. It is suggested that the formation of a clear modulation structure is responsible for the development of superconducting transition in the annealed films.