Abstract
FeSe1−xTex superconductor has a relatively simple crystal structure and a high superconducting transition temperature in bulk form at ambient pressure, which gives it great application potential. In this study, Nb is selected to partially replace Fe in FeSe0.4Te0.6 and a series of Fe1−xNbxSe0.4Te0.6 single crystals with x = 0, 0.01, 0.03, 0.06, and 0.1 were synthesized using the self-flux. The crystal structure and superconductivity are characterized by XRD and magnetization measurements. The fish-tail peak effect was observed in samples with x = 0, 0.01, and 0.03. The critical current density of the three samples with x = 0, 0.01, and 0.03 is estimated by using the Bean model. According to the Dew-Hughes model, the effect of Nb doping on the magnetic flux pinning behavior of FeSe0.4Te0.6 is also investigated.