Evaluation of magnetic shielding characteristics of bulk HTS including weak links with FEM analysis

Abstract

Some bulk high temperature superconductors (HTSs) are inhomogeneous due to weak links. Thus, we have measured distributions of the magnetic flux density on the HTSs surface using a Hall element, and evaluated its magnetic characteristics with a magnetic field visualization technique. However, the evaluation of the magnetic flux density at the actual surface layer of the HTS was difficult in the measurement using the Hall element. In this research, we examined the quantitative evaluation for the magnetic characteristics of the HTS including weak links with a three-dimensional finite element method (FEM) analysis in static magnetic fields. The distribution of the magnetic flux density at the actual surface layer of the HTS specimen and the diffusion of the magnetic flux in the space above the HTS surface were evaluated with FEM analysis. The validity of the proposed analytical method was confirmed by comparison with the experimental results and the verification of the analysis accuracy.