Effect of proton irradiation on superconducting fluctuations of SmBCO-coated conductor tapes

Superconductivity fluctuations are behaviors in which a finite probability of a Cooper pair above T_c due to thermal fluctuations produces excess conductivity. The dimensionality analysis of this behavior can accurately evaluate essential superconducting parameters such as the higher critical field and coherence length. To investigate the fluctuation effect of SmBa₂Cu₃O_7-δ (SmBCO) superconducting tapes and two types of proton-irradiated SmBCO tapes, we measured the temperature dependence of the detailed in-plane electrical resistivity at various magnetic fields and extracted the temperature dependence of the excess conductivity from these results. The excess conductivity was analyzed by the Aslamazov–Larkin (AL) theory and the Ullah and Dorsey (UD) scaling method. The fluctuations occurred in three dimensions in all samples regardless of the proton irradiation, and the evaluated higher critical field showed a significant increase due to the proton irradiation. Proton irradiation improves the operating potential at higher magnetic fields in high-T_c superconductors. These results show that SmBCO superconducting coated conductor tape is a versatile core industrial material.