Superconducting films with antidot arrays —Novel behavior of the critical current

Departement Fysica, Universiteit Antwerpen Groenenborgerlaan 171, B-2020 Antwerpen, Belgium

Received: 16 January 2006
Accepted: 3 March 2006

Abstract

Novel behavior of the critical current density j_c of a regularly perforated superconducting film is found, as a function of applied magnetic field H. Previously pronounced peaks of j_c at matching fields were always found to decrease with increasing H. Here we found a reversal of this behavior for particular geometrical parameters of the antidot lattice and/or temperature. This new phenomenon is due to a strong “caging” of interstitial vortices between the pinned ones. We show that this vortex-vortex interaction can be further tailored by an appropriate choice of the superconducting material, described by the Ginzburg-Landau parameter κ. In effective type-I samples we predict that the peaks in at the matching fields are transformed into a step-like behavior.