Electrical properties and AC susceptibility of FeS added YBa2Cu3O7−δ superconductor

Abstract

The opposing properties of superconductivity and magnetism are an interesting phenomenon. In this work, the effects of antiferromagnetic iron sulfide (FeS) addition on YBa2Cu3O7−δ superconductor were studied. Samples with nominal starting compositions YBa2Cu3O7−δ (FeS)x for x = 0–1.0 wt.% were prepared using the solid-state reaction method. X-ray diffraction patterns showed that the YBa2Cu3O7−δ phase and orthorhombicity were preserved with FeS addition. Scanning electron micrographs showed that addition of FeS decreased the average grain size while maintaining the grain morphology of granular structure. FeS does not suppress the onset transition temperature, Tc onset and AC susceptibility transition temperature, Tcχ, which were found to be in the range of 89–92 K and 92–93 K for all samples, respectively. However, the peak temperature, Tp of the imaginary part of the susceptibility and zero-resistance temperature, Tc zero were severely suppressed with FeS addition. The critical current density at the peak temperature of the imaginary part of the susceptibility, Jc(Tp) for all samples were calculated to be in the range of 16–19 A/cm2. This work showed that FeS affected the connectivity between the grains which weakened the intergranular coupling and decreased the flux pinning energy.