Passive Magnetic Shielding of Stacked Joint-free Superconducting Annular Disks Made of REBCO Tapes

Abstract

The joint-free superconducting annular disks and their stacks, obtained by cutting REBCO (REBa2Cu3O7–δ, RE: rare earth) wide tapes, are proposed as promising passive magnetic shields in this paper. The shielding properties of the disks have been numerically studied using the finite element method. The shielding factor (SF), defined as the ratio between the applied field and the central field, had a frequency-independent value when the magnetic field is much lower than the full penetration field. It appears to have a linear relationship with the ratio of the outer and inner diameter of the disk. Furthermore, various architectures with stacked disks were studied. High shielding factors (SF > 104) under enhanced full penetration fields of above 100 mT can be obtained in the configuration of more disks and proper disk distance (the distance between the disks on each layer). Two stacked disks were designed. In a 1-mT, 1-Hz applied field, the SF of the 4-mm inner diameter discrete stack is 1.21 × 107 (140 dB), and the SF of the 20-mm inner diameter split stack reaches 3.44 × 104 (90 dB). It implies that the stacked REBCO disks have great potential for the application of high-efficiency magnetic shielding.