Strongly nonequilibrium flux flow in the presence of perforating submicron holes

We report on the effects of perforating submicron holes on the vortex dynamics of amorphous Nb0.7Ge0.3 micro-bridges in the strongly nonequilibrium mixed state, when vortex properties change substantially. In contrast to the weak nonequilibrium-when the presence of holes may result in either an increase (close to T-c) or a decrease (well below T-c) of the dissipation, in the strong nonequilibrium an enhanced dissipation is observed irrespectively of the bath temperature. Close to T, this enhancement is similar to that in the weak nonequilibrium, but corresponds to vortices shrunk due to the Larkin-Ovchinnikov mechanism. At low temperatures the enhancement is a consequence of a weakening of the flux pinning by the holes in a regime where electron heating dominates the superconducting properties. (c) 2005 Elsevier B.V. All rights reserved.