Suspension of Soft Magnetic Materials Using High Tc Superconductors

Abstract

This paper describes a novel suspension technique using high Tc superconductors and magnetic materials. For a field-cooled superconductor and an adjacent magnetic material, it was found that the usual inverse relationship between the attractive magnetic force and gap distance reverts to a direct relationship for small gap length. Thus, stable, non-contact suspension is possible within a certain gap range. This phenomenon was found for even a soft magnetic material possessing a minimal coercive force. Since remarkable reversals were observed for magnetic materials with diameters much smaller than that of the pinned area, it is considered that some of the pinned flux is subject to a “gathering effect” in the magnetic material. Stable, contact-less suspension of a 180g carbon steel weight under a high Tc superconductor was achieved using this technique.