Alteration in the superconducting properties of Bi2Sr2CaCu2O8 crystals due to proton irradiation

The effects of proton irradiation on the superconducting properties of single-crystal Bi2Sr2CaCu2O8 are reported. Proton irradiation results in a lower transition temperature and increased transition width. Low-temperature critical currents are found to increase with increasing fluence. The irreversibility line moves significantly in both the low- and high-field regimes. Optimal movement of the line in the high-field regime is found to occur at a fluence corresponding to nearly one defect per vortex core disk. Implications for materials applications are discussed.