An Effective-Medium Method: The Phonon Mechanism of Anomaly Formation in the Magnon Spectrum of a Finite Magnetic Superlattice

摘要

An effective-medium method is developed and applied to calculate the effect of dynamic magnetoelastic interaction on the spin dynamics of a finite magnetic thin-layer superlattice in the long-wavelength approximation. It is shown that if the intra- and interlayer spin-spin interactions are predominantly due to indirect coupling via the long-range field of quasi-static magnetoelastic strains, then the magnon spectrum of such a superlattice exhibits anomalies which are absent in the usually considered case where collective spin-wave excitations are formed through magnetodipole interaction.