Influence of precursor oxygen stoichiometry on the formation of Hg, Re-1223 superconductors

Thanks to a novel technique (thermobaric analyser or TEA) for measuring the in situ pressure in quartz tubes, we have investigated the precursor quali ty for the synthesis of the superconductor Hg-1223 which is an essential pa rameter to control. We have made this study on the Hg(0.8)2Re(0.18)Ba(2)Ca( 2)Cu(3)O(x), samples and we can conclude that this superconductor phase req uires a ceramic precursor sintered in a low P-O2 mixture gas Bur. An excess ively oxygenated precursor leads to overdoped superconducting phases, prese nce of other members with lower n, HSCaO2 and some unreacted precursor. The precursor oxygenation degree also modifies the kinetics of formation of Hg CaO2 and the partial melting of the superconductor material may be affected .