Improvement of Granular Critical Current Density in Bi: 2212 Superconductors

We report here structural and superconducting properties of Bi1.7Pb0.3Sr2Ca YxCu2Oy superconductors with various x values (x= 0.00, x = 0.15). It is found that addition of Y3+ does not influence the phase purity of Bi: 2212, while lattice parameters are affected. Furthermore, the critical temperature Tc of Bi: 2212 is improved Y addition. On the other hand, the behavior of flux pinning and its impact on critical current density for pure and Y substituted samples is investigated. The magnetic hysteresis loops (MHLs) are measured over the temperature range (4 K < T < 75 K) using vibrating sample magnetometer (VSM) and at different fields up to 100000 Oe. The critical current density as a function of both temperatures and applied fields is estimated by using Beans model in terms of full width of magnetization loop ∆M. It is found that the partial substitution of Y chemical doping enhances the flux pinning in Bi: 2212 system and the critical current density is improved as well as critical temperature.