Melt-processing high-T{sub c} superconductors under an elevated magnetic field [Final report no. 2]

Abstract

Despite the fact that high critical current densities (JC' s) have been obtained in high temperature conductor (HTS) single crystals, the large-scale application of polycrystalline HTS, such as in wires, solenoids and magnets has been limited by the poor alignment of superconducting grains due to the presence of grain boundary weak links with low values of J, [l].Among the three major families of HTS, namely the Y-Ba-Cu-0 (YBCO), Bi-Sr-Ca-Cu-0 (BSCCO), the T1-Ba-Ca-Cu-0 (TBCCO) systems, the best wires produced so far have been made of BSCCO material [2]. In this system, three superconducting phases are known, in particular Bi-2201 (TC-20K), Bi-2212 (Tc-90K) and BI-2223 (Tc-l 1OK). The crystallographic c-axis perpendicular to the longitudinal plane (Fig. 1). Although significant results in the fabrication of BSCCO thick films and tapes have been obtained [3-51, further improvements are required in order to render these compounds suitable for large-scale applications. Hence, it is important to fully understand the mechanisms that lead to a highly textured microstructure.