High- Tc phase obtained in the Pb/Sb doped Bi–Sr–Ca–Cu–O system

Abstract

Partial replacement of Bi by Pb and Sb produces materials of high- T c pure phase, with antimony playing an important role in accelerating the formation of the phase with the higher superconductive transition in the Bi–Sr–Ca–Cu–O system. The influence of the antimony precursors on the superconducting phases mechanism formation was examined. Using a solid state reaction route, two nominal compositions Bi 1.6Pb 0.3Sb 0.1Sr 2Ca 2Cu 3Oy and Bi 1.6Pb 0.4Sb 0.1Sr 2Ca 2Cu 4Oy were investigated. The sources of antimony were Sb 2O 3, αSb 2O 4 and a prepared mixture Bi 1.9Sb 0.1O x . The mechanism formation of the phases upon annealing was investigated using X-ray diffraction and simultaneous thermal analysis. Electrical properties of the obtained materials were evaluated. The presence of the antimony ions determined a higher reactivity of the system as well as the promotion of the superconducting high- T c phase enhancement.