Publications

Superconductor samples of the type nanosized (ZnFe2O4)xGdBa2Cu3O7-δ were synthesized by the conventional solid-state reaction technique. The (ZnFe2O4) content x varied from 0 to 1.2 wt% of the samples total mass. Ion beam analysis (IBA) was performed to determine the elemental stoichiometry of superconducting samples. Furthermore, the prepared samples were also characterized using X-ray powder diffraction (XRD), scanning and transmission electron microscopes (SEM and TEM). The effect of the addition of ZnFe2O4 which acts as flux pinning centers was investigated measuring the electrical resistivity and ac magnetization at different applied magnetic fields. It was found that addition of the nanosized (ZnFe2O4) up to 0.06wt% enhances the critical current density Jc and the superconducting transition temperature Tc. On the other hand, the superconducting properties of these samples were deteriorated for x>0.06wt%. The irreversibility line was thermally activated. The logarithmic plot of Birr versus (1 − Tirr/Tc(0)) showed a crossover temperature, reflecting a transition from two- to three-dimensional behavior. The Birr-T curves are well fitted according to Matsushita's model which is based on the de-pinning mechanism caused by thermally activated flux creep.