Hybridization between chiral nutation modes in ferrimagnets

The hybridization between ferrimagnetic magnons of different chiralities holds potentials for applications in the design of magnonic devices. Whereas the nutation mode observed in the ferromagnetic film also possesses opposite chirality to precessional magnon mode, in the present work, we study the interplay of the nutation modes and chiral magnons in ferrimagnets with both parallel and antiparallel magnetic configurations based on the inertial Landau–Lifshitz–Gilbert equation. While the two configurations show some general features, such as the individual excitation of the nutation modes and the repulsion between nutation modes and conventional modes, the antiparallel configuration also exhibits a hybridization between two nutation modes and distinct dissipation behaviors, compared to the parallel configuration. A theoretical mode analysis was performed based on a perturbation approach, which nicely reproduces the observations in the simulation and clarifies the key role of the magnetic anisotropy in mode hybridization. Our findings offer a more comprehensive understanding of inertial effects in ferrimagnets, and could be useful for understanding experimental studies on ferrimagnets with non-negligible magnetic inertia.