Ferromagnetodynamics of parallel stripe domains - domain walls system

Abstract

Experimental observation of the Domain Wall Resonance (DWR) and the two modes of the Domain ferromagnetic Resonance (DR) was simultaneously made in demagnetized thin platelets of Ga substituted YIG. As an applied in-plane dc magnetic field, H p, is increased, the various resonance modes were observed to be coupled and repelled each other where they would nominally cross over, resulting in ‘frequency gaps’ in the frequency vs. H p dispersion relationship. A generalized theory of dynamics of parallel stripe domains and domain walls is proposed, which predicts the coupled resonance frequencies in good agreement with the experimental values. The theory also predicts the occurence and magnitude of the observed frequency gaps. Parameters used in the theory, such as the domain wall mass, are evaluated more accurately, taking into account the Q value of the films explicitly. This is found to lift the singularity in the DWR frequency at saturation as predicted in earlier models. The role of cubis anisotropy energy in the ferromagnetodynamics of the parallel stripe domains structure is also discussed qualitatively.