Superconducting fluctuations above T c in (Li1− x Fe x )OHFeSe single crystal

Abstract The magnetization and resistivity measurements have been done to investigate the superconducting fluctuations effect above the superconducting transition temperature ( T c ) in (Li 1− x Fe x )OHFeSe single crystal. These measurements were performed with applying the external magnetic fields in the ab plane of (Li 1− x Fe x )OHFeSe single crystal. By analyzing the diamagnetism response and excess conductivity, the behavior of superconducting fluctuations in the normal state is studied. The upper limit temperature of superconducting fluctuation is determined to be around 1.2 times larger than T c , suggesting that the superconducting fluctuation of (Li 1− x Fe x )OHFeSe is a large one. This exceeding value is obviously higher than the conventional superconductors. In addition, the superconductivity of (Li 1− x Fe x )OHFeSe coexists with the magnetism rooted in the (Li, Fe)OH layer and induced by magnetic field at low temperature.