Processing of textured BSCCO superconductors by laser-induced directional solidification

High-temperature superconductors based on BSSCO are interesting for applications in current lead systems required for superconducting magnets working at cryogenic temperatures as well as to facilitate the development of cryocooled turnkey units. The two BSCCO phases considered for applications at or below 77 K, the 110 K 2223 and the 90 K 2212, differ substantially in processing conditions. Some of these differences are presented and discussed in this paper, especially in connection with melt processing methods. Results obtained with the preparation of these phases using the laser float zone melting method are presented in order to analyse some of the most important differences between 2223 and 2212. Their melting and solidification behaviour is studied on the basis of the resultant microstructure and its relation to the critical currents obtained. The 2212 phase is shown to exhibit improved properties and processing conditions that make it more interesting from the fabrication point of view and for the applications considered here.