Analysis of superconducting response and flux pinning ability of (Mg0.8Zn0.2Fe2O4)x/CuTl-1223 composites

Abstract

The superconducting properties of (Mg0.8Zn0.2Fe2O4)x/Cu0.5Tl0.5–1223 matrix for concentrations (x = 0.0, 0.5, 1.0, 1.5 wt%) were synthesized by two-step solid state reaction method and analyzed by different characterization techniques. The magnetic Mg0.8Zn0.2Fe2O4 nanoparticles were synthesized by sol-gel technique separately and later inserted in CuTl-1223 superconducting matrix to obtain final product. The Mg0.8Zn0.2Fe2O4 nanoparticles were separately characterized by various techniques such as x-ray Diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive x-ray Spectroscopy (EDX) and Vibrating Sample Magnetometer (VSM). The superconducting (Mg0.8Zn0.2Fe2O4)x/CuTl-1223 composite samples (x = 0 ~ 1.5 wt%) were also characterized by various available characterization techniques. The XRD analysis showed spinel cubic structures of magnetic nanoparticles and tetragonal structure of superconducting composites. The XRD spectra revealed that the tetragonal structure of CuTl-1223 superconducting phase was not disturbed after the inclusion of magnetic Mg0.8Zn0.2Fe2O4 nanoparticles. The behavior of Mg0.8Zn0.2Fe2O4 was found ferromagnetic in nature during an applied magnetic field. The FTIR analysis exhibited results that Mg0.8Zn0.2Fe2O4 nanoparticles are settled at grain-boundaries and there is no major variation in oxygen modes. The value of critical temperature Tc(0) reduce with increase in magnetic nanoparticles content. The reduction in activation energy is also noticed with greater addition of magnetic nanoparticles. The overall suppression of critical parameters and activation energy values is due to the net spin of ferromagnetic natured Mg0.8Zn0.2Fe2O4 nanoparticles, which may scatter charge carriers and increase dissipation energy and ultimately result in pair breaking and resistive broadening to deteriorate flux pinning ability of the superconducting composite matrices.