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

The depinning current Ic versus applied magnetic field B close to the transition temperature Tc of Nb thin films with randomly diluted triangular arrays of antidots is investigated. % Our experiments confirm essential features in Ic(B) as predicted by Reichhardt and Olson Reichhardt [Phys.Rev. B 76, 094512 (2007)]. % We show that, by introducing disorder into periodic pinning arrays, Ic can be enhanced. % In particular, for arrays with fixed density n_p of antidots, an increase in dilution Pd induces an increase in Ic and decrease of the flux-flow voltage for B>Bp=n_p Phi_0.