OPTICAL INVESTIGATION OF DOMAIN RESONANCES IN MAGNETIC GARNET-FILMS

Magnetic garnet films of composition (Y,Ri)(3)(Fe,Al)(5)O-12 are grown by liquid phase epitaxy on [111] oriented substrates of Cd3Ga5O12. La ttices of parallel stripe domains are stabilized by astatic induction applied in the Film plane. The two branches DR of the domain resonance and the domain wall resonance DWR are excited by microwave magnetic f ields in the frequency range up to 6 GHz. Light passing thr stripe dom ain lattice parallel to the film normal is modulated at the excitation frequency. A modulation bandwidth of more than 2 GHz is observed. The resonances can be calculated with high accuracy by a hybridization mo del, if the quality factor Q of the film exceeds 0.5. For Q < 0.5 a si mple approximation is used to describe the superposition of the DR(+) and DR(-) resonances. The superposition model predicts two stability s tates of the resonance DR(+) which are observed experimentally. From t he optical measurements precession angles of the resonance DR(-) of ne arly 6 degrees and wall oscillation amplitudes up to 25 nm are derived .