Analysis of Measurement Method for Critical Current Density by Using Permanent Magnet

The permanent-magnet method for measuring critical current density in high-temperature superconducting thin films is numerically and experimentally investigated. Numerical results show that the critical current density is approximately proportional to the maximum repulsive force. Furthermore, the maximum repulsive force increases as the value of diameter of permanent magnet increases. This tendency is also observed in the experimental investigation. Finally, spatial distributions of the shielding current density are experimentally reproduced by the system.