Magnon-Phonon-Interaction-Induced Electromagnetic Wave Radiation in the Strong-Coupling Region

Abstract

We theoretically study the electromagnetic wave radiation of magnons driven by acoustic phonons in systems with strong magnon-phonon interaction. We evaluate the field dependence of radiation intensity spectra that exhibits the avoided crossing, a characteristic of strongly coupled systems. At the crossover where the magnon and phonon eigenstates are hybridized, we demonstrate the existence of two resonant radiation frequencies with circular polarization and the enhancement of antenna radiation efficiency by over 100 times. We can also reconfigure the ellipticity of the antenna polarization by changing the applied out-of-plane magnetic field. Our results open up possibilities of developing ultracompact antennas by using the hybridized magnon-phonon mode.