Interface mechanism of photon–magnon–phonon conversion in an epitaxial ferrite–dielectric structure

Abstract It is shown that in the transition layer of an epitaxial yttrium iron garnet (YIG) film, there are effects of intense power conversion and redistribution between electromagnetic waves (EMW), exchange spin waves (ESW) and acoustic waves (AW). These interconversion occurs during the casсade of double hybridization of EMW-ESW and secondary hybridization of ESW-AW. The necessary phase synchronism condition for this is ensured by the smooth distortion of the ESW dispersion within the thickness direction of the transition layer. The secondary hybridization of ESW-AW manifests itself in the intense excitation of AW, which are radiated into the depth of the gadolinium gallium garnet (GGG) substrate. In this case, magnetoacoustic resonances are excited in the YIG-GGG bilayer structure, for the observation of which strict parallelism and optical polishing of the reflecting surfaces of the YIG-GGG structures are required. An important advantage of magnetoacoustic resonances is the record high quality factor in the microwave range and high resistance to external atmospheric influences, which is of significant interest for the fabrication of highly stable magnetoacoustic microwave generators with discrete frequency tuning.