# Efficient spin excitation via ultrafast damping-like torques in antiferromagnets

## TL;DR

This paper reveals that ultrafast damping significantly influences spin dynamics in antiferromagnets, enabling highly efficient and rapid control of magnetic states for spintronic applications.

## Contribution

It demonstrates that ultrafast damping effects are crucial in antiferromagnets, leading to large-amplitude magnetic modulations during impulsive excitations, unlike in ferromagnets.

## Key findings

- Ultrafast damping causes immediate spin canting in antiferromagnets.
- Exchange and anisotropy interactions amplify spin canting effects.
- This mechanism enables ultrafast manipulation of antiferromagnetic order.

## Abstract

Damping effects form the core of many emerging concepts for high-speed spintronic applications. Important characteristics such as device switching times and magnetic domain-wall velocities depend critically on the damping rate. While the implications of spin damping for relaxation processes are intensively studied, damping effects during impulsive spin excitations are assumed to be negligible because of the shortness of the excitation process. Herein, we show that, unlike in ferromagnets, ultrafast damping plays a crucial role in antiferromagnets because of their strongly elliptical spin precession. In time-resolved measurements, we find that ultrafast damping results in an immediate spin canting along the short precession axis. The interplay between antiferromagnetic exchange and magnetic anisotropy amplifies this canting by several orders of magnitude towards large-amplitude modulations of the antiferromagnetic order parameter. This leverage effect discloses a highly efficient route towards the ultrafast manipulation of magnetism in antiferromagnetic spintronics.