Magnetic Shielding Effect of High-<i>T<sub>c</sub></i> Superconduction Cylinder Using the Ferromagnetic Cylinder

Abstract

As one of the basic research areas for the improvement of magnetic shielding effects and the fabrication of largesized cylinders, the present paper shows how the shielding is improved by superimposing a single- or doublemagnetic cylinder such as a soft iron cylinder over a high-critical-temperature (high-Tc) superconducting cylinder such as a Y-Ba-Cu-O (YBCO) cylinder. The value of the maximum shielded magnetic field (Bs) for the superimposed cylinder by using a double-magnetic cylinder was found about 50 times greater than that of a superconducting YBCO cylinder. The values of Bs are systematically measured by changing the lengths of single- and double-soft-iron cylinders at a temperature of 77.4K, and are analyzed by using several different models, with an important criterion being derived for designing an effective shield of the vessel. In addition, it was found that the experimental values of Bs agree well with theoretical values.