Search

Superconductor samples of type (CoFe2O4)xGdBa2Cu3O7-δ(0≤x≤0.1) were synthesized by the conventional solid-state reaction technique, whereas nanosized CoFe2O4was prepared by co-precipitation method with grain size of about 8.5 nm. The elemental content of the prepared samples was determined using particle induced X-ray emission (PIXE). The temperature dependence of real (χ') and imaginary (χʺ) components of AC magnetic susceptibility (ACMS) at different magnetic field amplitude (3–15 Oe) was investigated. The analysis of the temperature dependence of ACMS was performed using Bean critical state model. The values of the critical current density Jcat T> Tp(Tpis the inter-granular loss peak temperature) were calculated as a function of magnetic field and nanosized CoFe2O4content. It was found that the low nanosized CoFe2O4addition content (x= 0.01) improves the critical current density Jcof Gd-123 superconducting phase. The observed variation of Jcwith temperature indicated that the weak links are changed from superconductor–normal metal–superconductor (SNS) for free sample to superconductor–insulator–superconductor (SIS) type of junctions for samples added with nanosized CoFe2O4of x> 0.01. We also discussed the experimental results in the framework of the critical state model to estimate the effective volume fraction of the grains fgusing Cole–Cole plots.