Chirality of exchange spin waves exposed: Scattering and emission from interfaces between antiferromagnetically coupled ferromagnets

Abstract

We have studied the effect of chirality of the magnetization precession on the emission and scattering of spin waves from interfaces between ferromagnets with antiparallel magnetization. The need to match the chirality of the magnetization precessions at such interfaces promotes coupling between propagating modes on one side of the interface and evanescent modes on the other. This leads to the following two major effects: (i) an asymmetrical (ultimately, unidirectional) emission of spin waves from such interfaces when they are driven by an elliptically polarized magnetic field, and (ii) a strong (ultimately, complete) suppression of the transmission of spin waves incident upon such interfaces. Our results are relevant to the construction of spin-wave devices and more generally to the interpretation of measurements and numerical simulations in the field of chiral magnonics.