Enhancement in the high-T_cphase of BSCCO superconductors by Nb addition

Abstract

Pure and Nb2O5 added Bi1.6Pb0.4NbxSr2Ca2Cu3Oδ superconductors (x varies up to 0.30) were synthesized by the solid state reaction method. Structural and superconducting properties of the samples were investigated. The fraction of the high-Tc phase (2223) increases with Nb addition up to x = 0.10, for which a nearly single 2223 phase was obtained. The critical temperature of the samples increases from 96 to 104 K with doping up to x = 0.20 and a further increase in Nb decreases the Tc sharply. Similarly, there is a considerable enhancement in the critical current density (jc) of the samples in the same doping range. Both AC susceptibility and transport measurements showed that the optimum Nb concentration is x = 0.20. The out-of-phase component of the AC susceptibility measurements showed that inter-grain coupling was enhanced up to the same doping level. Nb additions above x = 0.30 decrease the fraction of the high-Tc phase and degrade the superconducting properties. Present measurements indicate that x = 0.20 is the optimum Nb concentration in the BSCCO superconductor to enhance phase purity, inter-grain coupling and superconducting parameters (Tc and jc).

Effect of high valency cations on the (BiPb)2Sr2Ca3Cu4O12+δ compounds

“…Nevertheless, there are few reports on the effects of substitutions to Cu sites in the BSCCO (2223) system. It is recently observed that niobium, vanadium, and titanium addition increases the (2223) phase considerably and succeeded to isolate this phase up to 96% and 97% [17,18]. In this study, we desire to investigate both the effect of the sintering time on the formation of the high T c phase and the effect of other high valency cations like vanadium and titanium.…”

Investigation of Niobium (Nb) Substitution on Structural and Superconducting Properties of (Bi, Pb)-Based Superconductors

“…and Naghshara, H. [11] [12] [13]. Among these phases, the Bi-2223 phase with the chemical formula of Bi 2 Sr 2 Ca 2 Cu 3 O 10+y appears to be suitable for superconducting devices which are operating at a temperature of liquid nitrogen (T > 77 K) [14]. But the formation of pure Bi-2223 phase is a critical issue in fabricating BSCCO superconductors.…”

Effect of Cerium adding and Titanium doping on the BPSCCO Superconductor Materials

“…It have been produced the (BiPb) 2 Ce x Sr 2 Ca 3 Cu 4-y Ti y O 12+δ compounds for x = 0.05 ve y = 0, 0.05, 0.1, 0.2 by conventional solid state reaction method. The effects of cerium adding and Ti doping on the structure have been investigated by electrical resistance, XRD patterns and magnetic hysteresis loop measurements.…”