Critical Current Density and Grain Connectivity of Bi-2223 added MgB2 Superconductor

Polycrystalline MgB2 with addition of 0, 1, 3, and 5 wt. % of Bi-2223(Bi1.8Pb0.26Sr2Ca2Cu3O10+x) powder has been synthesized by solid reaction process. The effect of Bi-2223 addition on current transport and superconducting properties of polycrystalline MgB2 superconductor is discussed. Four probe DC resistivity measurement shows that low level of Bi-2223 addition hardly affects the superconducting transition temperature, T-c of MgB2. The modified Bloch-Gruneisen (B-G) analysis of normal state resistivity data reveals a decrease in intergrain connectivity and increase in intragrain connectivity of MgB2 by Bi-2223 addition. The critical current density of present set of samples is estimated from M-H hysteresis loop in the light of Bean's model. MgB2 added with 1 wt. % of Bi-2223 added gives the best performance (similar to 2 times enhancement in J(c)) amongst the studied samples.