Interaction between polarization waves and spin waves in magnetodielectrics

Abstract

Microscopic mechanisms of interactions between magnons and optical phonons in antiferro- and ferri-magnetic ionic dielectrics are formulated. Following some earlier work, this is achieved by taking cognizance of the mixing of the excited orbital states with the ground orbital states of the magnetic ions due to lattice vibrations.It is found that the processes which involve splitting of an optical phonon into two magnons are most important for the exchange of energy between the spin and lattice systems. Relaxation frequencies for such processes for antiferro- and ferri-magnetic systems at various temperatures are calculated. In the systems under consideration, processes involving acoustic phonon-magnon interaction dominate below 10°K; however, the optical phonon-magnon contribution becomes quite appreciable around 25°K.