Imaging non-collinear antiferromagnetic textures via single spin relaxometry

TL;DR

This paper introduces a novel all-optical method using a single nitrogen-vacancy defect in diamond to image non-collinear antiferromagnetic textures at the nanoscale by detecting local magnetic noise from thermal magnons.

Contribution

The study demonstrates a new nanoscale imaging technique for antiferromagnetic textures using NV center relaxometry, enabling visualization of complex spin structures without net magnetization.

Findings

Successfully imaged domain walls, spin spirals, and skyrmions in synthetic antiferromagnets.

Proved the method's effectiveness for various spin textures.

Extended the potential for studying antiferromagnetic physics and magnonics.

Abstract

Antiferromagnetic materials are promising platforms for next-generation spintronics owing to their fast dynamics and high robustness against parasitic magnetic fields. However, nanoscale imaging of the magnetic order in such materials with zero net magnetization remains a major experimental challenge. Here we show that non-collinear antiferromagnetic spin textures can be imaged by probing the magnetic noise they locally produce via thermal populations of magnons. To this end, we perform nanoscale, all-optical relaxometry with a scanning quantum sensor based on a single nitrogen-vacancy (NV) defect in diamond. Magnetic noise is detected through an increase of the spin relaxation rate of the NV defect, which results in an overall reduction of its photoluminescence signal under continuous laser illumination. As a proof-of-concept, the efficiency of the method is demonstrated by imaging various spin textures in synthetic antiferromagnets, including domain walls, spin spirals and antiferromagnetic skyrmions. This imaging procedure could be extended to a large class of intrinsic antiferromagnets and opens up new opportunities for studying the physics of localized spin wave modes for magnonics.