Vortex-penetration field at a groove with a depth smaller than the penetration depth

TL;DR

This paper derives an analytical formula to evaluate the vortex-penetration field at grooves on superconducting surfaces, aiding the understanding of vortex behavior in materials like nitrogen-doped Nb, Nb3Sn, or NbN.

Contribution

The paper introduces a new analytical formula for vortex-penetration fields at grooves smaller than the penetration depth in extreme type II superconductors.

Findings

Analytical formula applicable to various superconducting materials.

Enhanced understanding of vortex behavior at surface grooves.

Potential improvements in superconducting cavity design.

Abstract

Analytical formula to evaluate the vortex-penetration field at a groove with a depth smaller than penetration depth is derived, which can be applied to surfaces of cavities or test pieces made from extreme type II superconductors such as nitrogen-doped Nb or alternative materials like Nb3Sn or NbN.