Melt Textured Bulk Superconductor

Oxide bulk high-temperature superconductors, RE-Ba-Cu-O, are composite materials of which compose a non-superconducting phase, RE₂BaCuO₅, and superconducting phase, REBa₂Cu₃O_y. These materials have been commonly fabricated by so-called the top-seeded melt growth process in which involves melting, seeding and solidifying. One of the typical applications of the bulk superconductors is a quasi-permanent magnet. The bulk superconductors can solely achieve this kind of unique applications, since its heat capacity is much higher than that of low temperature superconductors. The field trapping potential of the bulk superconductors is proportional to the product of the sample critical current density, J_c, and the size of the loop defined by the supercurrent. As a result, enhacement of J_c, coupled with fabrication of larger, weak link free grains, is a general processing aim for improving the field trapping capability of bulk high-temperature superconductors.

Fig. 30 mm sized Ag added Gd-Ba-Cu-O single grain can easily trap a significant large field

of 1.4 T at liquid nitrogen temperature, whereas the corresponding size of conventional NdFeB

permanent shows only 0.3 T.