Systemitic investigation has been made on the relation among oxygen content, crystal distortion, heat treatment and superconductivity in Y-Ba-Cu-O system. It was found that oxygen content and distortion have very important effect on the superconductivity of Y-Ba-Cu-O system. The effect of Fe and Go impurity on superconductivity of YBa_2 Cu_3 O_7 -x has been investigated. The results show that Tc and diamagnetic susceptibity decrease, crystal structure changes from being orthorhombic to a tetragonal system with increasing Fe and Co content. The oxygen in 1D Cu-O chain which can be released during heating decreased with increasing Co content. The oxygen absorption relief and diffusion have also been investigated in Y-Ba-Cu-O system. reversible oxygen relief and absorption appeared during heating and cooling in the temperature range of 400-950 ℃, This process can be described a reversible chemical equiliblium. oxygen ability in phase transformation has been proposed. The oxygen relief and absorption in Bi-Ca-Sr-Cu-O system appeared in the temperature range of 800-880 ℃. It has been calculated from solid reaction that the average valence of copper in the sample quenched and furnace-cooled are +2 and +2.1-2.2, respectively. Amorphous and casting Bi-Ca-Sr-Cu-O sample were prepared by melt splat quenching technique. The heat treatment, superconductivity, crystllization, phase transformation and corresponding the change of paramagnetic susceptibility have been investigated. Crystallization activation has been calculated. Five solid state phase transformations and oxygen absorption were observed in the temperature range of 20-880 ℃. According to investigation of susceptibility during crystallization of amorphous Bi-Ca-Sr-Cu-O sample, It was found that x-T relation obeys Curie-Weiss rule before forming 2212 phase and paramagnetic susceptibility did not change with temperature after forming superconducting phase.
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