Improvement of Critical Current Density in Bi-2223 Superconductor by Ag-Doping

High-Tc superconducting polycrystalline Bi-2223 undoped sample (A0) and 5wt.% Ag-doped sample (A5) have been prepared by solid-state reaction method at 8550C with sintering time of 8 days. X-ray powder diffraction (XRD) results shown that the major phase of these samples is Bi-2223. The volume ratio of Bi-2223 phase observed to be increased from 78% for undoped sample (A0) to 95% for 5wt.% Ag-doped sample (A5). The enhancement of the onset of high-Tc superconductivity (Tc,onset = 112.5 K) in silver doping sample was observed by DC-resistivity measurements. From the AC-susceptibility measurements combined with Bean critical state model, the temperature dependent parabolic law of inter-granular or matrix critical current density (Jcm) was fitted. Some Jcm values were estimated from these parabolic laws. The results showed that 5wt% Ag-doping can make the Bi-2223 sample with nearly double critical current density.