Synthesis and characterization of PbO–CdO nanocomposite and its effect on (Bi,Pb)-2223 superconductor

A PbO–CdO nanocomposite-added Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀ ((Bi,Pb)-2223) superconductor has been prepared. The effect of the PbO–CdO nanocomposite addition on the transport critical current density (J_c) of (Bi,Pb)-2223 superconductor was investigated. The transition temperature (T_c−onset), zero electrical resistance temperature (T_c−R=0), and J_c of the samples were measured by the four-probe method. Phase formation, structure, and microstructure of samples were investigated. The distribution of nanoparticle size was determined. The results indicated that the PbO–CdO-added samples showed larger grain size and an increased volume fraction of high-T_c phase (Bi-2223) compared to the non-added sample. A slight increase in T_c−R=0 of x = 0.15 wt% was observed. J_c of the PbO–CdO nanocomposite-added samples was significantly higher than for the non-added sample. That could be explained by the possibility that the PbO–CdO nanocomposite acts as an effective flux pinning center in (Bi,Pb)-2223. At 77 K, J_c of x = 0.15 wt% added sample was more than 20 times larger than J_c of the non-added sample (x = 0 wt%). A combined effect of enhanced flux pinning, increased fraction of high-T_c phase and improved grain size, which led to increase in the J_c of added samples, is discussed.