Electrical, Structural, and Thermal Properties of Ferrite/Superconductor (Ni_0.5Zn_0.5Fe₂O₄)_x/YBa₂Cu₃O_7-δ) Nanocomposite Materials

The superconductor YBa₂Cu₃O_7-δ (Y123) is prepared by the solid-state route, while the nanosized Ni_0.5Zn_0.5Fe₂O₄ (Ni-Zn ferrite) is synthesized via citric acid sol-gel technique. The composite material of the type (Ni_0.5Zn_0.5Fe₂O₄)_x/YBa₂Cu₃O_7-δ, where x = 0.00, 0.03, 0.10, and 0.50 wt%, is prepared by a modified solid-state method to study the effect of doping Ni-Zn nanosized ferrite on the superconducting, structure, and thermal properties of Y123. The prepared samples show Meissner effect which confirmed the presence of superconducting phase at liquid nitrogen temperature (77 K). The prepared samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion of X-ray (EDX), infra-red (IR) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), DC resistance by four-probe, and critical current density measurements. It was found that by increasing Ni_0.5Zn_0.5Fe₂O₄ nanoparticles in the Y123 compound, the unit cell volume of the orthorhombic phase decreases, but the transition temperature T_c and critical current density J_c decrease for low doping (x = 0.03 wt%) then increase (x = 0.10 and 0.50 wt%) for Ni_0.5Zn_0.5Fe₂O₄ doped in Y123. The transport properties of the (Ni_0.5Zn_0.5Fe₂O₄)_x/YBa₂Cu₃O₇-_δ composite as electrical resistance R, T_c, and J_c are interpreted according to Bean's critical state model and charge-vortex interaction combined with vortex pinning in Y123 high-T_c mixed-state type-II superconductor.

Highlights

The critical current density J_c decreased for low doping of nanosized Ni-Zn ferrite into Y123 with ratio of 0.03 wt% and increased by increasing doping ratio to 0.50 wt%. The physical properties are improved by the coexistence of the superconductor Y123 and nanosized Ni-Zn ferrites in nanocomposite material.