  We explore the hybridization of fundamental material resonances with the
artificial resonances of metamaterials. A hybrid structure is presented in the
waveguide environment that consists of a resonant magnetic material with a
characteristic tuneable gyromagnetic response that is integrated into a
complementary split ring resonator (CSRR) metamaterial structure. The combined
structure exhibits a distinct hybrid resonance in which each natural resonance
of the CSRR is split into a lower and upper resonance that straddle the
frequency for which the magnetic material's permeability is zero. We provide an
analytical understanding of this hybrid resonance and define an effective
medium theory for the combined structure that demonstrates good agreement with
numerical electromagnetic simulations. The designed structure demonstrates the
potential for using a ferrimagnetic or ferromagnetic material as a means of
creating a tunable metamaterial structure.
