Effect of Co0.5Zn0.5Fe2O4 Nanoparticle on AC Susceptibility and Electrical Properties of YBa2Cu3O7-δ Superconductor

Magnetism and superconductivity are mutually exclusive phenomena and their interaction is an interesting topic to study. In this work the effect of Co0.5Zn0.5Fe2O4 (CZFO) nanoparticle with size 20- 50 nm on YBa2Cu3O7-delta(YBCO) is reported. The samples were prepared using solid state reaction with starting composition YBa2Cu3O7-delta(Co0.5Zn0.5Fe2O4), with x = 0 to 0.4 weight percent (wt. %). All samples exhibited single YBCO phase as shown from the XRD patterns. The grain size was reduced with CZFO addition. The transition temperature (T-c) from resistance measurements showed a slight increase from 90 K (x = 0) to 91 K (x = 0.1) followed by a suppression for x >= 0.2. The peak temperature, T-p of the imaginary part of the susceptibility chi '', was around 79 to 76 K in the x = 0 to 0.3 samples. However, a drastic decrease to 60 K was observed in the x = 0.4 sample indicating weakening of intergrain coupling which resulted in coupling losses as CZFO was added. The x = 0.1 sample showed the highest T-c and the critical current density, J(c) among all the samples studied. These results were compared with other materials addition to YBa2Cu3O7-delta.