Levitation forces between a finite rectangular superconductor and a spherical magnet

Abstract

A model to describe the interaction between a spherical permanent magnet and a square superconductor in the mixed state was elaborated. The proposal is based on image dipole ideas as is the case of the Frozen dipole model that has been used in the literature. More precisely, a frozen dipole was put in the center of the superconducting sample; this dipole ``was born" when the first critical field was reached in that position. This led to the attractive force magnet-superconductor in the penetrated-field state. In the description of the Meissner state, the demagnetizing field was not included in the calculation. Both vertical and horizontal forces are discussed.