Interaction of Magnons with Longitudinal and Transverse Phonons (H in a [111] Direction)

An analysis of the parallel pumping of magnetoelastic waves near the magnon-longitudinal-phonon and magnon-transverse-phonon crossover regions is presented. Equations of motion describing magnon-longitudinal-phonon and magnon-transverse-phonon interactions have been derived when H0 is along [111] crystallographic direction and transverse phonons are not essentially polarized along H0. Expressions describing the shape of the critical rf field vs dc field are obtained for both cases. The wavevector of the magnetoelastic waves that are excited by parallel pumping changes discontinuously with the d.c. field strength. Additional remarks on the influence of the elastic anisotropy on the discussed interactions are presented.