Suppression of dissipation in Nb thin films with triangular antidot arrays by random removal of pinning sites

Abstract

The depinning current ${I}_{c}$ versus applied magnetic field $B$ close to the transition temperature ${T}_{c}$ of Nb thin films with randomly diluted triangular arrays of antidots is investigated. Our experiments confirm essential features in ${I}_{c}(B)$ as predicted by Reichhardt and Olson Reichhardt [Phys. Rev. B 76, 094512 (2007)]. We show that, by introducing disorder into periodic pinning arrays, ${I}_{c}$ can be enhanced. In particular, for arrays with fixed density ${n}_{p}$ of antidots, an increase in dilution ${P}_{d}$ induces an increase in ${I}_{c}$ and decrease of the flux-flow voltage for $B>{B}_{p}={n}_{p}{\ensuremath{\Phi}}_{0}$.