Czechoslovak Journal of Physics vol:46 pages:885-886
We have studied the magnetization (M(H)) and critical currents (I-c(H)) of superconducting a-W0.67Ge0.33 films with a square array of submicron holes (antidots) having a fixed periodicity of 1 mu m for different antidot sizes. Pronounced anomalies are present in M(H) and I-c(H) when the external magnetic field is equal to a matching field. For small antidot sizes the nucleation of Abrikosov vortices at interstitial positions occurs, leading to a drastic reduction of the critical currents. For large antidots, a crossover to a wire network regime is observed.