Thermal suppression of surface barrier in ultrasmall superconducting structures

Abstract

In the recent experiment by Cren \textit{et al.} [Phys. Rev. Lett. \textbf{102}, 127005 (2009)], no hysteresis for vortex penetration and expulsion from the nano-island of Pb was observed. In the present paper, we argue that this effect can be associated with the thermoactivated surmounting of the surface barrier by a vortex. The typical entrance (exit) time is found analytically from the Fokker-Planck equation, written in the form suitable for the extreme vortex confinement. We show that this time is several orders of magnitude smaller than 1 second under the conditions of the experiment considered. Our results thus demonstrate a possibility for the thermal suppression of the surface barrier in nanosized low-$T_c$ superconductors. We also briefly discuss other recent experiments on vortices in related structures.

12 pages, 2 figures

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Cited by in corpus (5)

• Saddle point states in 2D superconducting film biased near the depairing current
• Fluctuations in superconducting rings with two order parameters
• Geometry-induced localization of thermal fluctuations in ultrathin superconducting structures
• Thermally Assisted Penetration and Exclusion of Single Vortex in Mesoscopic Superconductors
• Vortex quantum tunnelling versus thermal activation in ultrathin superconducting nanoislands