Pinning of a Vortex Line to a Small Defect in Superconductors

Abstract

It is shown that quasiparticle scattering by a defect in a superconductor leads to large elementary pinning energies of flux lines. In the case of a small radius ($R$) point defect the new mechanism outweighs the traditional volume effect by the factor $\frac{{\ensuremath{\xi}}_{0}}{R}$.