The magnetooptic and magnetic properties of hexagonal arrays of holes in optically thin iron films are presented. We analyze their dependence on the hole radius and compare the results to a continuous iron film of same thickness. We observe a large enhancement of the magnetooptic Kerr rotation with respect to that of the continuous film, at frequecies where surface plasmons excitations are expected. Additional simulations are in very good agreement with the experiment and thus confirm the effect of the surface plasmons on the Kerr rotation. The altering of the magnetic properties by the hole array is also visible in the hysteretic behavior of the sample where a dramatic change is observed.

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