Theory of pinning in a superconducting thin film pierced by a ferromagnetic columnar defect

M. Amin Kayali

doi:10.1103/PhysRevB.71.024515

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Theory of pinning in a superconducting thin film pierced by a ferromagnetic columnar defect

M. Amin Kayali

DOI 10.1103/PhysRevB.71.024515 · Physical Review B

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Abstract

This paper presents analytical study of a system consisting of a superconducting thin film pierced by ferromagnetic columnar defects. The magnetic fields, the screening currents, the energy and the pinning forces for this system are calculated. The interaction between the magnetic field of vortices and the magnetization outside the plane of the film or its close proximity leads to very strong pinning. If the magnetization of the columnar defect exceeds a critical value then a spontaneous vortex phase appears. All these results are also generalized for the case when the superconductor is pierced by an array of columnar defects. Vortices in this system are pinned by a pinning force that increases linearly with the magnetization of the magnetic defect.