Proposal of magnetic circuit using magnetic shielding with bulk-type high-Tc superconductors - Evaluation of magnetic circuits using toroidal core

Recently, bulk-type high-Tc superconductors (HTSs) having a characteristic of critical current density over 104 A/cm2 in liquid nitrogen (77 K) and at 1 T have been produced. They are promising for many practical applications such as a magnetic bearing, a magnetic levitation, a flywheel, a magnetic shielding, and others. In this research, we propose a magnetic circuit that can be used as a magnetic shield for several superconductors as an application of the HTS. It is a closed magnetic circuit by means of a toroidal core. Characteristics of the magnetic circuit surrounded with HTSs are evaluated and the possibility is examined. Because the magnetic circuit of the ferrite core is surrounded with HTSs, the magnetic flux is shielded even if it leaks from the ferrite core. © 2004 Wiley Periodicals, Inc.