Effects of He Ion Irradiation on Superconductivity of Bi-Sr-Ca-Cu-O Films

Abstract
The zero resistance transition temperatures T c (R=0) decrease remarkably from 92 K to 62 K in a Bi-Sr-Ca-Cu-O film irradiated with 400 keV He ions to a dose of 1.1×1019/m2 at room temperature. Resistivities above transition temperatures increase with increasing the dose, while transition temperatures T c (onset) are relatively unaffected by He ion irradiations. The decrease in the transition temperatures and the resistivity increase after low-temperature irradiations at 85 K are larger than those after room temperature irradiation.