  In this paper, matters considering the immersion of gold nanoparticles inside
a magnetic medium are investigated experimentally and theoretically. Three
samples with periodic arrays of Au cylinders where studied: particles on a
surface of the magnetic dielectric film, inside the magnetic film and directly
under the magnetic film. The largest LSPR mediated Faraday rotation resonance
enhancement takes place for the case of the nanoparticles submerged inside the
magnetic film. Optimal place for nanoparticles is under the magnetic medium
surface at 6 nm deep in the considered configurations. It is shown that the
most influence on the Faraday rotation enhancement is produced by the magnetic
properties of the medium between the nanoantennas. The experimental results are
in good agreement with the numerical analysis.
