Superconducting sphere and finite-size permanent magnet: force, torque, and alignment effect calculation

Using a local first-order interaction model, previously described, the force and torque between a superconducting sphere in the Meissner state and a finite-size permanent magnet are calculated. These findings are compared to results obtained by other models for the force based on the images method for a point magnetic dipole. It is demonstrated that the first-order calculation is a good approximation. Moreover, the torque between a superconducting sphere and a magnet in different positions and angular orientations is calculated for the first time. We describe the alignment effect that tends to align a magnet tangentially to the superconducting sphere surface. In addition, it is shown that the finiteness of the magnet reduces the magnitude of the repulsive force.

Superconducting sphere and finite-size permanent magnet: force, torque, and alignment effect calculation Articles