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

The effect of bismuth ferrite (BiFeO3) nanoparticles (~ 20 nm) on Bi1.6Pb0.4Sr2Ca2Cu3O10 (Bi-2223) superconductor was studied. Bi-2223 powders with starting formula Bi1.6Pb0.4Sr2Ca2Cu3O10(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 (Tc-onset = 118 K, Tc-zero = 106 K). The highest transport critical current density, Jct 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, Tp 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 Ni0.5Zn0.5Fe2O4, Cr2O3, NiFe2O4, MgO, ZnO and Co3O4 in improving the transition temperatures and critical current density of the Bi-2223 phase superconductor. [ABSTRACT FROM AUTHOR]