  The transverse magneto-optical Kerr effect (TMOKE) in magnetite-based
magneto-plasmonic crystals is studied experimentally and theoretically. We
analyze angle-resolved TMOKE spectra from two types of structures where noble
metallic stripes are incorporated inside a thin magnetite film or located on
top of a homogeneous film. A multiple wide band enhancement of the TMOKE signal
in transmission is demonstrated. The complex dielectric permittivity and
gyration are experimentally determined using the ellipsometry technique as well
as Faraday rotation and ellipticity measurements. The obtained parameters are
used in rigorous coupled wave analysis (RCWA) calculations for studying the
optical resonances. Our RCWA calculations of transmittance and TMOKE are in
good agreement with the experimental data. The role of guiding and plasmonic
modes in the TMOKE enhancement is revealed. We demonstrate that the TMOKE
provides rich information about the studied optical resonances.
