AC Susceptibility and Electrical Properties of BiFeO3 Nanoparticles Added Bi1.6Pb0.4Sr2Ca2Cu3O10 Superconductor

The effect of bismuth ferrite (BiFeO₃) nanoparticles (~ 20 nm) on Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀ (Bi-2223) superconductor was studied. Bi-2223 powders with starting formula Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀(BiFeO₃)_x for x = 0–0.20 wt.% were prepared using the co-precipitation method. The temperature dependent electrical resistance measurements showed the highest superconducting transition temperature for the x = 0.10 wt. % sample (T_c-onset = 118 K, T_c-zero = 106 K). The highest transport critical current density, J_ct at 40 K was shown by the x = 0.02 wt. % sample (21.93 A cm⁻²). The peak temperature of imaginary part of susceptibility, T_p was much higher compared with the non-added sample, indicating BiFeO₃ nanoparticles enhanced the flux pinning energy and intergranular coupling. The addition of a small amount of BiFeO₃ nanoparticles (0.02–0.04% wt.%) increased the transport critical current density while further additions (0.06–0.20 wt.%) improved the superconducting transition temperatures. BiFeO₃ nanoparticles slightly suppressed the formation of the Bi-2223 phase, but it increased the transport critical current density by more than eleven times demonstrating BFO could act as effective pinning centres and enhanced connectivity between grains. This work showed that BiFeO₃ was better than other nanoparticles such as Ni_0.5Zn_0.5Fe₂O₄, Cr₂O₃, NiFe₂O₄, MgO, ZnO and Co₃O₄ in improving the transition temperatures and critical current density of the Bi-2223 phase superconductor.