Superconductivity of Bi2Sr2Can−1CunOy (n=2, 3, 4, and 5) thin films prepared in situ by molecular-beam epitaxy technique

Preparation techniques and properties of Bi-Sr-Ca-Cu-O thin films are reported. The optimization of the substrate temperature in ozone atmosphere and the shuttering of molecular beams on an atomic scale enabled us to prepare thin films of Bi2Sr2Can−1CunOy (n=1, 2, 3, 4, and 5). These films showed superconducting transition with the exception of the n=1 phase and resistivities showed strong temperature dependence without heat treatment after deposition. Reflection high-energy electron diffraction showed sharp streaks, which suggest the growth of films with flat surface on an atomic scale.