Processing and Properties of Oxide Superconductors

High temperature superconductivity in oxide superconductors such as Y-Ba- Cu-O, Bi-Sr-Ca-Cu-O, and Tl-Ba-Ca-Cu-O generated unprecedented excitement in view of their immense technological potential. However, the progress toward major applications of the bulk, oxide superconductors has been hindered by their low critical current densities (caused by severe conduction anisotropy and weak-link behavior) as well as the brittleness inherent in most ceramic materials. In this paper, various processing methods to induce a desirable microstructure such as the alignment of fibrous crystals parallel to the superconducting basal plane (e.g., Melt-Textured-Growth) will be described. Transport critical current densities as high as 17000 A/cm sup 2 have been accomplished in polycrystalline bulk Y-Ba-Cu-O by such microstructural control.