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Synthesis of Bi(Pb)-2223 from two different precursors with the same stoichiometry

V. MIHALACHE1,* , G. ALDICA1, P. BADICA1,2

Affiliation

  1. National Institute of Materials Physics, Bucharest-Magurele, POB MG-7, 077125 Romania
  2. Institute for Materials Research, Tohoku University. 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 Japan

Abstract

Samples of (Bi,Pb)2Sr2Ca2Cu3O10 (Bi(Pb)-2223) phase have been fabricated from two different oxide precursors with the same stoichiometry, synthesized by solid state reaction in the air at 815°C for 20 h. The first precursor was prepared by mixing Bi2O3, PbO, SrCO3, CaCO3 and CuO powders, while the second one through mixing Bi2O3 and PbO with Sr2Ca2Cu3Ox produced from SrCO3, CaCO3 and CuO powders. Pellets from the two precursors were prepared in the same conditions; heat treatment time was varied and intermediate grindings were applied. Although the maximum attained Bi(Pb)- 2223 phase amount was about 50% and above 90% in the samples from the two precursors, respectively, the samples from the first precursor have generally shown better superconducting properties such as the critical temperature from resistivity measurements and intragrain critical current Jcg from magnetic susceptibility measurements. For our particular case the influence of the final heat treatment is relatively low and at the same time the precursor plays a major role in controlling growth processes and final superconducting properties. Lower room-temperature Seebeck coefficient of the thermoelectric power for the samples fabricated from the first precursor suggests that one mechanism through which this control is realized might be the modification of the oxygenation level in the samples produced from different precursors. It was also found that for the samples prepared from the two precursors, intermediate grinding after 110h or more of heat treatment enhances density, almost does not influence Jcg (or slightly improves it), decreases Tc, and does not influence significantly the amount of Bi(Pb)-2223 phase..

Keywords

Bi(Pb)-2223, Precursors, Density, Transport parameters, Critical temperature, Intragrain critical current.

Submitted at: Nov. 14, 2006
Accepted at: June 15, 2007

Citation

V. MIHALACHE, G. ALDICA, P. BADICA, Synthesis of Bi(Pb)-2223 from two different precursors with the same stoichiometry, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 6, pp. 1767-1771 (2007)