Superconducting properties of Bi 2− xPb xSr 2Ca 2Cu 3O y system derived via sol–gel and solid state routes

Abstract

Bulk Pb doped Bi 2− x Pb x Sr 2Ca 2Cu 3O y ( x = 0.4 and 0.5) superconductors have been prepared via sol–gel route (SGR) using pure metal acetate precursors and solid state route (SSR) using conventional carbonate-oxide compounds. Variation of the percentage of high- T C phase (2223-phase) for samples prepared by different routes were observed from XRD data and it was found that SGR samples have higher percentage of (2223) phase than the SSR samples. It was ∼75% and ∼78% for SSR samples and ∼85% and ∼95% in SGR samples for doping composition of x = 0.4 and x = 0.5, respectively. The highest zero bulk resistance temperature ( T C( R = 0)) of 104 K was found in SGR sample ( x = 0.5), while the lowest T C( R = 0) value of 98 K was measured in SSR sample ( x = 0.4). Complex ac susceptibility measurements showed that the nature of the grains, grain boundaries and coupling associated to the superconducting properties were superior in SGR samples, hence sol–gel route appears to be a more suitable method in the preparation of single-phase BSCCO superconductor.