Critical Current Density and AC Susceptibility of Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀ Superconductor with Ni_0.5Zn_0.5Fe₂O₄ Nanomaterial

The juxtaposition of superconductivity and magnetism is an interesting research topic due to the exclusivity nature of both phenomena. In this paper, we report the effect of nanosized (~ 5 nm) nickel zinc ferrite Ni_0.5Zn_0.5Fe₂O₄ (NZFO) on Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀ (Bi-2223) superconductor. Bi-2223 powders were prepared using the co-precipitation method. Samples with starting formula Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀(Ni_0.5Zn_0.5Fe₂O₄)_x for x = 0 to 0.1 wt% have been prepared. The structure, microstructure, electrical resistance, and AC susceptibility were determined. The transport critical current density, J_ct, was measured using the 1 μV/cm criterion. The non-added sample sintered for 48 h showed the highest zero resistance temperature, T_c-zero (105 K) and J_ct of 1.83 A cm⁻² at 40 K. The x = 0.02 wt% sample sintered for 48 h (T_c-zero = 103 K) showed the highest J_ct of 5.30 A cm⁻² at 40 K. The peak temperature of the imaginary part of the complex susceptibility, T_p, increased with sintering time and nanoparticle addition, indicating full flux penetration occurred at higher temperatures and improved intergrain coupling. NZFO nanoparticle did not suppress the transition temperature but it improved the transport critical current density by more than five times indicating it enhanced flux pinning and connectivity between grains in the Bi-2223 phase.