Study of nano-sized (ZnFe2O4)y particles/CuTl-1223 superconductor composites

Zinc ferrite (ZnFe2O4)(y) nanoparticles/Cu0.5Tl0.5Ba2Ca2Cu3O10-delta (CuTl-1223) superconductor composites with y = 0-2 wt.% were prepared by adding ZnFe2O4 nanoparticles into CuTl-1223 superconductor matrix and characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transforms infrared (FTIR) spectroscopy and dc-resistivity (rho) measurements. The bulk CuTl-1223 superconductor matrix was synthesized by solid-state reaction and Zinc ferrite (ZnFe2O4) nanoparticles were separately prepared by sol-gel method. XRD analysis revealed the tetragonal and spinel structure of CuTl-1223 superconductor and ZnFe2O4 nanoparticles, respectively. The XRD analysis showed that increased concentration of ZnFe2O4 nanoparticles doesn't disturb the tetragonal structure of host CuTl-1223 superconductor matrix and has no appreciable effect on its lattice parameters. The SEM images confirm the granular structure of the host superconductor matrix. The presence of ZnFe2O4 nanoparticles in host superconductor matrix is confirmed by using FTIR study. Variation of zero resistivity critical temperature {T-c (0)) depends upon the concentration of the nanoparticles in the host superconductor matrix. The overall suppression of T-c (0) and diamagnetism with increasing nanoparticles concentration is most probably due to trapping of mobile free carriers and reflection of spin charge due to presence of paramagnetic ZnFe2O4 nanoparticles. There is possibility for the incorporation of Fe and Zn in the lattice sites during the synthesis process, which may also cause the reduction of T-c (0) of the final composites. (C) 2013 Elsevier Masson SAS. All rights reserved.