Synthesis of Hg_1−XRe_xBa₂Ca₂Cu₃O_8+x Pure Phase at Normal Pressures

Abstract

High purity ceramics of the superconducting phases Hg_1−xRe_xBa₂Ca₂Cu₃O₈ have been prepared by the vacuum sealed quartz tube techniques. The superconductors were obtained using precursor powders of Ba₂Ca₂Cu₃O_x mixed with stoichiometric additions of ReO₂ and HgO. The reaction was carried out in two steps: Firstly, the Ba₂Ca₂Cu₃O_x was homogenised and annealed with ReO₂ in oxygen atmosphere. Finally, the powders were mixed and pressed with stoichiometric additions of HgO and were encapsulated in an evacuated quartz tube and annealed at different rates and temperatures in order to optimise the purity of the phase.