Processing and Characterization of High T sub c Ceramic Superconductors

Since the discovery of superconductivity in the Ba-Y-Cu-O system about a year ago, and more recently in the Bi-Sr-Ca-Cu-O system, it has been a challenge to understand and improve the transport properties of these materials. Single crystal and thin film work demonstrate that current densities in the 10 sup 5 - 10 sup 6 A/cm sup 2 range can be achieved in the Ba-Y-Cu-O system. Yet conventionally prepared ceramic material still carries typically less than 500 A/cm sup 2. In addition to low Jc values, the ceramic material is affected adversely by the presence of relatively low magnetic fields.