Determination of the magnetic penetration depth with measurements of the vortex-penetration field for type-II superconductors

TL;DR

This paper presents a method to determine the London penetration depth in type-II superconductors by measuring the vortex-penetration field, considering geometrical and Bean-Livingston barriers, using surface magnetic induction data.

Contribution

It introduces a novel approach to extract the London penetration depth from vortex-penetration field measurements accounting for surface barriers.

Findings

Derived the vortex-penetration field considering geometrical and Bean-Livingston barriers.

Provided a practical method to determine the London penetration depth from surface magnetic induction measurements.

Enabled estimation of the lower critical field from vortex-penetration data.

Abstract

Using a known distribution of the Meissner currents over the surface of an infinitely long superconducting slab with a rectangular cross section, we find an applied magnetic field at which vortices begin to penetrate into the superconductor. This vortex-penetration field is determined by an interplay of the geometrical and Bean-Livingston barriers. The obtained results enable one to find the lower critical field and the London penetration depth from measurements of the magnetic induction on the surface of the superconducting slab, using, e.g., the micro-Hall probes.