Effect Of Preparation On Hg-Ba-Ca-Cu-O Superconductors

Some main features of the non-linear synthesis process are described by theoretical considerations. Results of typical preparation methods are compared to each other and to those obtained by the experiments designed specially for the study of the effect of synthesis on the superconducting properties of Hg-Ba-Ca-Cu-O compounds. As is shown, the controlled Hg-vapour pressure method, the sealed tube with phase formation procedure, the high-pressure synthesis and the freeze-drying method seem to be unambiguously reliable to provide high-quality samples. Significant deviations from these fundamental synthesis routes can lead to significant deviations of superconducting parameters.