Trapped magnetic field of a superconducting bulk magnet in high-Tc RE-Ba-Cu-O

Superconducting magnets made of high-T-c superconductors are promising for industrial applications. It is well known that REBa2Cu3O7-x and LRE (light rare-earth) Ba2Cu3O7-x superconductors prepared by melt processes have a high critical current density, J(c), at 77 K and high magnetic fields. Therefore, the materials are very prospective for high magnetic field application as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. LREBaCuO bulks, compared with REBaCuO bulks, exhibit a larger J(c) in high magnetic fields and a much improved irreversibility field, H-irr, at 77 K. In this study, we discuss the possibility and trapped field properties of a superconducting bulk magnet, as well as the melt processing for bulk superconductors and their characteristic superconducting properties. One of the applications is a superconducting magnet for the future magnetically levitated (Maglev) train.