Superconducting properties of bulk Bi1.6Pb0.4Sr2Ca2-xCdxCu3O10 system prepared via conventional solid state and coprecipitation methods

摘要

The effect of Cd doping on the superconducting properties of BSCCO system with nominal starting compositions of Bi1.6Pb0.4Sr2-Ca2-xCdxCu3O10 (x = 0.00-0.10) was studied. The preparation methods used to prepare the samples are the conventional solid-state oxide powder (SSR) and the coprecipitation (COP) techniques. Resistivity versus temperature measurements (R-T) showed that all doped samples exhibited metallic behaviour. For the SSR samples, existence of a two step feature was observed at x = 0.07 indicating the presence a lower temperature 2212 phase together with the higher temperature 2223 phase. This behaviour resulted in the shifting of the T-C(R=0) towards lower temperature. However, the COP samples showed better superconducting properties probably due to higher homogeneity resulted from mixing of sub-micron particles during sintering. The R-T curve did not display any two step features due to the single phase nature of the samples. This is confirmed by the XRD data where Bi-2212 phase was minor. In addition, small amount of doping (x = 0.02 in COP and SSR samples) enhanced the phase formation and T-C(R=0). (C) 2007 Elsevier B.V. All rights reserved.