SUPERCONDUCTING CUPRATES PREPARED BY THE MELT QUENCH PROCESS AND CONTAINING EXCESS Y OR ADDITIVES

Bulk YBaCuO samples doped with excess Y or other additives (including rare earths and Nb) and prepared by means of the melt quench process exhibit high magnetization and diamagnetic susceptibility. These can be attributed to the formation of a microstructure which is highly aligned and has few cracks and voids. These characteristics are associated with the presence of a second phase. The importance of this study lies in its applicability to the preparation of polycrystalline superconducting oxides with very high Jc values through careful control of their microstructure, in particular through the use of non-stoichiometric formulations and the introduction of additives in conjunction with melt-based processing methods. © 1990.