Fabrication and flux-trapping experiments of a 198 mm×99 mm bulkmagnet using YBCO superconductors

Abstract

We fabricate a 198 mm/spl times/99 mm bulk magnet, which consists of YBaCuO bulk superconductors that are 33 mm/spl times/ 33 mm in size and 10 mm in thickness in six columns and three rows. Bulk superconductors in this configuration are packed in one or two layers. The bulkmagnet is magnetized by the field-cooling method. The external magnetic field applied to the bulk superconductors is almost uniform at 1.1 T-1.2 T. The bulk superconductors are cooled by liquid nitrogen. As a result of the magnetization, the bulkmagnet can attract clips and mine tools on the surface of the outer vessel like a permanent magnet. The magnetic field at 3 mm from the surface of the outer vessel is larger than 0.14 T in the case of two layers.