In this study, high-Tc superconducting polycrystalline Bi-2223 undoped sample (A0) and 5wt Ag-doped sample (A5) were prepared by solid-state reaction method at 8550C with sintering time of 8 days. The X-ray powder diffraction (XRD) results show that the major phase of these samples was Bi-2223. | VNU Journal of Science Mathematics Physics Vol. 35 No. 4 2019 41-51 Original Article Improvement of Critical Current Density in Bi-2223 Superconductor by Ag-Doping Nguyen Khac Man1 Nguyen Duc Hoa1 Duong Thi Thanh Nhan2 1 International Training Institute for Materials Sience ITIMS Hanoi University of Science and Technology 1 Dai Co Viet Hanoi Vietnam 2 Faculty of Physics VNU University of Science 334 Nguyen Trai Hanoi Vietnam Received 05 June 2019 Revised 26 June 2019 Accepted 26 June 2019 Abstract In this study high-Tc superconducting polycrystalline Bi-2223 undoped sample A0 and 5wt. Ag-doped sample A5 were prepared by solid-state reaction method at 8550C with sintering time of 8 days. The X-ray powder diffraction XRD results show that the major phase of these samples was Bi-2223. The volume ratio of Bi-2223 phase 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 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 show that 5wt Ag- doping can nearly double critical current density in the Bi-2223 sample. Keywords Bi-2223 Ag-doping Jcm. 1. Introduction Bismuth strontium calcium copper oxide or BSCCO pronounced quot bisko quot is a family of high- temperature superconductors having the generalized chemical formula Bi2Sr2Can-1CunO2n 4 x. with n 1 2 and 3 etc. discovered as a general class in 1988 1 BSCCO was the first high- temperature superconductor which did not contain a rare earth element. It is a cuprate superconductor an important category of high-temperature superconductors sharing a two-dimensional layered perovskite ____ Corresponding author. Email address nkman@ https .
