Effects of Cr doping on the superconductivity and magnetism of FeTe0.8S0.2

Abstract

We investigate the effects of Cr doping on the superconductivity and magnetism of layered compound FeTe0.8S0.2, and find evidences for coexistence of ferromagnetism and superconductivity in the Cr-doped system. X-ray diffraction (XRD) spectra suggest that Cr dopants in Fe1-xCrxTe0.8S0.2 for x = 0.02, 0.04 and 0.06 primarily enter the sites in-between the FeTe1-ySy (0 < y ≤ 0.2) layers. Magnetic measurements reveal that the interlayer Cr dopants establish long-range ferromagnetic order with a doping dependent Curie temperature. On the other hand, the onset of superconductivity remains largely unaffected by the Cr-doping, although the superconducting transition width increases with increasing Cr doping while the superconducting diamagnetism decreases. Our observation suggests the compatibility of interlayer ferromagnetism with superconductivity in layered Fe1-xCrxTe0.8S0.2 compounds, similar to previous findings in other layer superconductors such as the cuprates and BiS2-based compounds.