Synthesis and Characterization of Nb Substitution on (Bi-Pb)-2223 Superconductors

Abstract

In this study, samples of were prepared by solid-state reaction method and the effect of Nb substitution for Pb on the structural and superconducting properties of this material was investigated. The room-temperature X-ray diffraction patterns indicated that all the samples have the dominant phase of high- (Bi-2223). However, other phases such as Bi-2212 and some impurity phases like , , and CuO were also obtained from XRD patterns. An increasing amount of substitutions for led to a phase transition from Bi-2223 to Bi-2212. Electrical resistivity and magnetic measurements revealed that the critical temperature and the critical current density decreases with increasing Nb content due to the enhancement of Bi-2212 phase and appearance of impurities. SEM images indicated that samples porosity changes due to the disrupted grain growth with the substitution of Pb ions with Nb ions.