Magnetic Flux Motion of Superconducting Bi-Sr-Ca-Cu-O Films after Ion Irradiation

Abstract
The temperature dependence of electrical resistance under applied magnetic fields was measured by the resistive method in polycrystalline Bi-Sr-Ca-Cu-O films after He ion irradiation at room temperature. The broadening of the transition temperature in the low resistance region was suppressed as the irradiation fluence increased. The effective activation energy was raised by ion irradiation. These changes are due to the presence of pinning centers produced by ion irradiation.