# Coherent Terahertz Spin-Wave Emission Associated with Ferrimagnetic Domain Wall Dynamics

## TL;DR

This paper theoretically demonstrates that applying a DC magnetic field to ferrimagnetic domain walls can generate terahertz spin-wave emission, a phenomenon not observed in ferromagnetic or antiferromagnetic systems, facilitated by Dzyaloshinskii-Moriya interaction.

## Contribution

It reveals a novel mechanism for terahertz spin-wave emission driven by ferrimagnetic domain wall dynamics influenced by Dzyaloshinskii-Moriya interaction and spin-orbit torque.

## Key findings

- DC magnetic field induces terahertz spin-wave emission in ferrimagnetic domain walls.
- Dzyaloshinskii-Moriya interaction enhances spin-wave emission and domain wall mobility.
- Spin-orbit torque combined with Dzyaloshinskii-Moriya interaction enables fast domain wall motion with terahertz emission.

## Abstract

We theoretically study the dynamics of ferrimagnetic domain walls in the presence of Dzyaloshinskii-Moriya interaction. We find that an application of a DC magnetic field can induce terahertz spin-wave emission by driving ferrimagnetic domain walls, which is not possible for ferromagnetic or antiferromagnetic domain walls. Dzyaloshinskii-Moriya interaction is shown to facilitate the teraherz spin-wave emission in wide ranges of net angular momentum by increasing the Walkerbreakdown field. Moreover, we show that spin-orbit torque combined with Dzyaloshinskii-Moriya interaction also drives a fast ferrimagnetic domain wall motion with emitting terahertz spin-waves in wide ranges of net angular momentum.