Flux confinement by regular arrays and clusters of antidots in Pb/Cu bilayers

We have studied the magnetoresistance and superconducting–normal phase boundary of superconducting films with an antidot array and mesoscopic antidot clusters of 2 × 2 μm²with only four antidots. For both systems characteristic minima have been observed in the magnetoresistance which are caused by the formation of certain vortex configurations minimizing the free energy. By comparing experimental data with calculations carried out in the London limit of the Ginzburg Landau theory, these vortex configurations have been identified.