Shock-wave-like emission of spin waves induced by the interfacial Dzyaloshinskii-Moriya interaction

We investigated spin wave (SW) propagation and emission in thin film systems with strong interfacial Dzyaloshinskii-Moriya interaction (DMI) utilizing micromagnetic simulation. The effect of DMI on SW propagation is analogous to the flow of magnetic medium leading to the spin Doppler effect, and a spin-polarized current can enhance or suppress it. We demonstrate that for a Doppler velocity exceeding a critical value, a shock-wave-like emission of SWs with a cone-shape emerges from a magnetically irregular point as the cone apex. The cone angle is quantitatively determined by the DMI-induced Doppler velocity. Combining the interfacial DMI and the spin-polarized current, a constant SW emission by a static source is demonstrated, which provides a promising route to efficiently generate SWs with tunable frequency.

Automated summary

In this study, we investigated the propagation and emission of spin waves (SWs) in thin film systems with strong interfacial Dzyaloshinskii-Moriya interaction (DMI) using micromagnetic simulation. We found that DMI affects the propagation of SWs in a way analogous to the spin Doppler effect caused by the flow of magnetic medium, and this effect can be enhanced or suppressed by a spin-polarized current. Furthermore, by combining the interfacial DMI and the spin-polarized current, we demonstrated a continuous emission of SWs from a static source, providing a promising approach to generate SWs with tunable frequency.