We report enhanced magneto-optical Kerr rotation in the layer systems of a magnetic granular film coated by uniform gold and dielectric films. The Kerr rotation spectra measured from 1.2 to show a peak at about , not present in either uncoated magnetic particle films. It was shown that the polar magneto-optical Kerr signal is about five times higher than that obtained for CoFe-MgO granular films in similar conditions. The physical nature of the magneto-optical effect enhancement in three layers (magnetic/noble/dielectric films) is related to the excitation of surface plasmons and their fast propagation on the interface of a complex three-layer structure. The Kerr rotation enhancement corresponds to intrinsic electronic transitions in the CoFe nanogranules due to the spectral overlap of these transitions with propagating surface plasmons.
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