Mechanics of vortex escape from extended linear defect in 3D-anisotropic superconductor

Abstract

The problem of vortex depinning from extended linear defect in 3D -anisotropic superconductor under the Lorentz force influence is considered for the case T =0. We treat it as a problem of classical mechanics behavior of an elastic vortex string which is settled in a potential well of linear defect and exerted to the Lorentz force action on its end within the screening layer of width λ (λ - is the London penetration depth) near the specimen surface. We search the stability problem and obtain conditions for the instability threshold, as well as the critical current density jc, at which the instability leading to vortex depinning first emerges near the surface and then propagates inside the superconductor. This scenario of vortex depinning mechanism at low temperatures is strongly supported by some recent experiments.