Surface nucleation of superconductivity near a current-carrying core

Abstract

A calculation is given of the azimuthal surface nucleation field of a type II superconductor which hosts a current-carrying core. The spatially inhomogeneous azimuthal external magnetic field is that due to a current of uniform density thought to be passed along the axis of a core. Upon increasing the current, the field increases to a critical value at which a phase transition from the superconducting to the normal state occurs. The magnetic field lines are parallel to the curvature of the superconductor–core heterointerface, hence the required critical field is Hc 3, the surface-sheath nucleation field.