Changes in superconducting properties of Nb films irradiated with Kr ion beam

초록

This study investigated the effect of Kr ion beam irradiation on the superconducting properties of Nb thin films, which are known for their high superconducting transition temperature ( T c ) at ambient pressure among single elements. Using the Stopping and Range of Ions in Matter (SRIM) program, we analyzed the distribution of Kr ions and displacement per atom (DPA) after irradiation, finding a direct correlation between irradiation amount and DPA. In samples with stronger beam energy, deeper ion penetration, fewer ions remained, and higher DPA values were observed. X-ray diffraction (XRD) revealed that the Nb (110) peak at 38.5 degrees weakened and shifted with increasing irradiation. T c decreased in all samples after irradiation, more significantly in those with higher beam energy. Irradiation raised resistivity of the film and lowered the residual -resistivity ratio (RRR). AC susceptibility measurements were also consistent with these findings. This research could potentially lead to more efficient and powerful superconducting devices and a better understanding of superconducting materials.

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