# Low spin wave damping in the insulating chiral magnet Cu$_{2}$OSeO$_{3}$

## TL;DR

This study demonstrates that the insulating chiral magnet Cu$_{2}$OSeO$_{3}$ exhibits exceptionally low spin wave damping, making it promising for high-frequency spintronic applications involving non-collinear spin structures.

## Contribution

The paper reports broadband microwave spectroscopy measurements revealing very low Gilbert damping in Cu$_{2}$OSeO$_{3}$, highlighting its potential for spintronic devices.

## Key findings

- Gilbert damping parameter of about 1×10^{-4} at 5 K
- Detection of sharp resonances attributed to confined spin waves
- Insulating chiral magnets are promising for high-frequency applications

## Abstract

Chiral magnets with topologically nontrivial spin order such as Skyrmions have generated enormous interest in both fundamental and applied sciences. We report broadband microwave spectroscopy performed on the insulating chiral ferrimagnet Cu$_{2}$OSeO$_{3}$. For the damping of magnetization dynamics we find a remarkably small Gilbert damping parameter of about $1\times10^{-4}$ at 5 K. This value is only a factor of 4 larger than the one reported for the best insulating ferrimagnet yttrium iron garnet. We detect a series of sharp resonances and attribute them to confined spin waves in the mm-sized samples. Considering the small damping, insulating chiral magnets turn out to be promising candidates when exploring non-collinear spin structures for high frequency applications.