Stray-field imaging of magnetic vortices with a single diamond spin

TL;DR

This paper demonstrates the use of a single nitrogen-vacancy (NV) diamond spin as a nanoscale, quantitative magnetic field sensor to image and analyze magnetic vortices in nanostructures with high precision.

Contribution

It provides the first three-dimensional, vectorial, and quantitative imaging of magnetic vortices using NV magnetometry, validating its effectiveness for nanomagnetic studies.

Findings

Successful imaging of magnetic vortex stray fields

Excellent agreement with micromagnetic simulations

Detection of vortex core in nanostructures

Abstract

Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with nanometer scale spatial resolution remains an outstanding challenge. Recently, a new technique has emerged that employs a single nitrogen-vacancy (NV) defect in diamond as an atomic-size magnetometer. Although NV magnetometry promises significant advances in magnetic imaging, the effectiveness of the technique, when applied to realistic magnetic nanostructures, remains to be demonstrated. Here we use a scanning NV magnetometer to image a magnetic vortex, which is one of the most iconic object of nanomagnetism, owing to the small size (~10 nm) of the vortex core. We report three-dimensional, vectorial, and quantitative measurements of the stray magnetic field emitted by a vortex in a ferromagnetic square dot, including the detection of the vortex core. We find excellent agreement with micromagnetic simulations, both for regular vortex structures and for higher-order magnetization states. These experiments establish scanning NV magnetometry as a practical and unique tool for fundamental studies in nanomagnetism.