# Ultrafast and Energy-Efficient Quenching of Spin Order: Antiferromagnetism Beats Ferromagnetism

## TL;DR

This study demonstrates that antiferromagnetic order in metallic dysprosium can be quenched faster and more efficiently by femtosecond laser pulses than ferromagnetic order, revealing a new angular momentum transfer mechanism.

## Contribution

It uncovers a distinct and efficient angular momentum transfer process in antiferromagnets, offering a potential pathway for energy-efficient magnetic device control.

## Key findings

- Antiferromagnetic dynamics are faster than ferromagnetic ones under laser excitation.
- Antiferromagnetic order is more efficiently manipulated by optical pulses.
- A new interatomic angular momentum transfer channel is identified.

## Abstract

By comparing femtosecond laser pulse induced ferro- and antiferromagnetic dynamics in one and the same material - metallic dysprosium - we show both to behave fundamentally different. Antiferromagnetic order is considerably faster and much more efficiently manipulated by optical excitation than its ferromagnetic counterpart. We assign the fast and extremely efficient process in the antiferromagnet to an interatomic transfer of angular momentum within the spin system. Our findings do not only reveal this angular momentum transfer channel effective in antiferromagnets and other magnetic structures with non-parallel spin alignment, they also point out a possible route towards energy-efficient spin manipulation for magnetic devices.