Magnetic force acting on a magnetic point dipole over a superconducting thin film with a circular defect

Abstract

London theory is used to calculate the magnetic levitation force acting on the magnetic point dipole placed above the type-II superconducting thin film with a circular defect. The condition of the position of point dipole to create the first vortex in the thin film is found for b much less than boolean AND. The difference of the lateral magnetic force Delta F-r acting on the point dipole between with and without a single vortex created in the thin film is also derived and used to estimate the force to overcome the pinning force of the vertex due to the circular defect.