Effect of Te-doping on the superconducting characteristics of FeSe single crystal

Abstract FeSe1-xTex (x = 0.5, 0.6 and 0.7) single crystals were prepared by the chemical reaction sealed in a small quartz tube with high vacuum. The angular dependence of resistance was measured in different magnetic field at a constant temperature, and scaled by the anisotropic Gingzburg-Landau theory, respectively, for these single crystals. The field dependences of critical temperature and flux pinning energy were obtained from resistance versus temperature curves measured in various magnetic fields perpendicular and parallel to the c-axis. The critical current density and the flux pinning force were calculated by the Bean model from the magnetization loops. The Te-doping had an obvious effect on the critical temperature Tc, the critical current density Jc and the flux pinning energy U; but there was a weak effect on the anisotropy of FeSe1-xTex single crystals. The flux pinning characteristics were also discussed.