The recently discovered (Li${ _{ 1-x}}$Fe${ _x}$)OHFeSe superconductor with $T_c$ about 40K provides a good platform for investigating the magnetization and electrical transport properties of FeSe-based superconductors. By using a hydrothermal ion-exchange method, we have successfully grown crystals of (Li${ _{ 1-x}}$Fe${ _x}$)OHFeSe. X-ray diffraction on the sample shows the single crystalline PbO-type structure with the c-axis preferential orientation. Magnetic susceptibility and resistive measurements show an onset superconducting transition at around ${ T_c}$=38.3K. Using the magnetization hysteresis loops and Bean critical state model, a large critical current ${ J_s}$ is observed in low temperature region. The critical current density is suppressed exponentially with increasing magnetic field. Temperature dependencies of resistivity under various currents and fields are measured, revealing a robust superconducting current density and bulk superconductivity.
Categories: cond-mat.supr-con