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

TL;DR

This paper demonstrates that interfacial Dzyaloshinskii-Moriya interaction can induce shock-wave-like emission of spin waves, which can be controlled and tuned using spin-polarized currents, offering new ways to generate and manipulate spin waves.

Contribution

It reveals the shock-wave-like emission of spin waves caused by DMI and spin-polarized currents, providing a novel method for tunable spin wave generation.

Findings

Shock-wave-like spin wave emission occurs at a critical Doppler velocity.

The cone angle of emitted spin waves is determined by DMI-induced Doppler velocity.

Static sources can produce continuous spin wave emission when combined with spin-polarized currents.

Abstract

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. It is demonstrated 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.