Evaluation by numerical analysis of magnetic shielding characteristics of bulk high-T_c superconductor containing weak links

High-T_c superconductors (HTS), which have the characteristics of critical current density over 3 × 10⁴ A/cm² at liquid nitrogen temperature (77 K) and 1 T, can be produced. Thus, they are promising for many practical applications such as a magnetic bearing, magnetic levitation, flywheel, and magnetic shielding. Since the HTS characteristics are not homogeneous in some specimens due to grain boundaries and cracks, the distribution of magnetic characteristics should be assessed. Thus, we have measured the distribution of the magnetic flux density on the surface of the HTS using a Hall element, and have evaluated its magnetic characteristics. The measurement of magnetic characteristics using a Hall element is difficult regarding the distribution of the magnetic flux density on the actual surface and inside of the HTS sample. In this research, we conducted a quantitative evaluation of the magnetic shielding characteristics of the HTS including weak links under a static magnetic field with the three-dimensional finite element method analysis.