Anatomy of Spin Wave Polarization in Ferromagnets

Abstract: Spin waves in ferromagnetic materials are predominantly characterized by right-handed circular polarization due to symmetry breaking induced by net magnetization. However, magnetic interactions, including the external magnetic field, Heisenberg exchange, Dzyaloshinskii-Moriya interaction, and dipole-dipole interaction, can modify this behavior, leading to elliptical polarization. This study provides a systematic analysis of these interactions and their influence on spin wave polarization, establishing principles to predict traits such as polarization degree and orientation based on equilibrium magnetization textures. The framework is applied to diverse magnetic configurations, including spin spirals, domain walls, and Skyrmions, offering a comprehensive yet simple approach to understanding polarization dynamics in ferromagnetic systems.