ABSTRACT
The possibility of concentrating and manipulating light at unprece-
dentedly low size scales by means of surface electromagnetic waves
such as surface plasmon polaritons (SPPs) or localized surface
plasmons (LSPs), well below the diffraction limit, opens a strikingly
broad spectrum of fundamental and practical applications such as
plasmonic circuits, plasmonic lenses, light trapping, biosensors, and
cancer treatment, among many others. Nevertheless, for many of
these applications it is important to have external control of the
propagation of such plasmonic resonances, for example, using exter-
nal magnetic fields. In this chapter we will discuss how adequately
inserting magneto-optically active metals such as ferromagnetic
transition metals in systems with plasmonic properties such as thin
films, multilayers, and nanostructures imparts to them a strong
sensitivity to external magnetic fields. In turn these systems exhibit
also a remarkable increase of the magneto-optical activity due to
interaction of the strong electromagnetic fields generated by the
plasmonic excitations and the magneto-optically active materials.