Thermoanalytical Studies on Preparation Conditions of Superconducting YBa2Cu3O7-y

概要

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We studied the decarbonation process of a ternary mixture of Y2O3, BaCO3 and CuO or Cu2O by TG-DTA analysis to clarify the optimum condition for the preparation of YBa2Cu3O7-y ceramics, which are superconducting above 90 K. We found that a narrow temperature region, $940{\sim}950$°C, is desirable for the decarbonation process. Furthermore, we observed an anomaly at ${\sim}600$°C in DTA curves of stoichiometric YBa2Cu3O7-y ceramics and nonstoichiometric Y–Ba–Cu–O samples. From the strong correlation between the magnitude of this anomaly and the composition of the ceramics, the anomaly was attributed to the orthorhombic-tetragonal phase transition in the YBa2Cu3O7-y phase. It was also found that the composition dependence of $T_{\text{c}}$ of the ceramics correlates strongly with that of the magnitude of the anomaly.
INSTITUTE OF PURE AND APPLIED PHYSICSの論文
1989-03-20