Munetsugu Matsuo

Superconductivity in High Tc Rare Earth–Ba–Cu Oxide

We report the superconductivity in rare earth–Ba–Cu–O system and the identification of the phase responsible for superconducting behavior. The Tc offset for the La compound is comparable to that observed for Y–Ba–Cu–O. We also found that mixed rare earth compounds are high Tc superconductors. Some results on magnetic properties are also given.

Microstructural Characterization of YBa2Cu3O7-x Prepared by the Quench and Melt Growth (QMG) Process

The bulk material of YBa2Cu3O7-x prepared by the Quench and Melt Growth (QMG) process was characterized from microstructural and crystallographic points of view. Microscopic observation showed that the material was a composite of YBa2Cu3O7-x (123) matrix and Y2BaCuOy (211) dispersoids with striations and cracks. Because the material was highly oriented, analysis of the crystal structure was carried out by means of a modified method of texture analysis. It was found that the matrix consisted of only a few twinned crystallites of the order of 10-2m. The QMG-processed material was concluded to be a large grain composed of 123 crystallites containing a fine dispersion of 211 phase.