Influence of proton and gamma irradiation on the Tco of Bi-system superconductors

Bi-system superconductors, prepared by solid state reaction method and nitrate method, were irradiated by 20 MeV proton and gamma ray caused by proton irradiation. The Tco (zero resistance temperature) and gamma ray intensity was measured to show that Tco increases first by gamma ray irradiation and then decreases gradually. The results indicated that there are two completive effects on the sample's Tc during gamma irradiation. First is the excited carrier composed Cooper-pairs, with higher energy gap to increase Tco. Second is the irradiation defect to destroy superconduction microstructure, and hence decrease Tc. The results of proton irradiation showed the monotonic decrease on Tc