4 Reports on Experimental Results 4.22 Magneto-optical enhancement in Co | Au patterned nanostructures

The Þeld of plasmonics is growing rapidly nowadays due to the progress in the fabrication of nanostructures. The latter, together with a deeper understanding of the underlying physics have led to a variety of possible applications ranging from physics to photonics and from chemistry to biology, from sensing [2] to microscopy [3] and to telecommunications [4]. Ag and Au are traditionally the noble metals that are used by the plasmonic community due to their low losses in the visible range. Previous investigations have avoided the use of magnetic materials due to the presence of absorptive losses for the plasmons. However, due to the advances in nano-patterning the last decade, combined structures composed of plasmonic and ferromagnetic materials allowed the coupling between plasmonic and magnetic states through the utilization of magneto-optic (MO) effects [5, 6]. Such a coupling has shown that MO effects like polar MO and transverse MO Kerr effect can be largely enhanced in the presence of plasmonic resonances [79]. In this Report we focus on the enhancement of the polar magneto-optic Kerr effect (P-MOKE) in hexagonal patterned structures of Co | Au multilayers. The multilayer is grown on top of a mask of with polystyrene spheres with diameter d = 220nm and pitch size a = 470nm. We show that the efÞciency of the magneto-plasmonic interaction can be drastically enhanced by multilayers and b