Quantum Sensing of Spin Transport Properties of an Antiferromagnetic Insulator

TL;DR

This paper demonstrates a non-invasive optical method using NV quantum sensors to measure intrinsic spin transport properties in antiferromagnetic insulators, providing new insights into their potential for spintronic applications.

Contribution

It introduces a novel NV center-based relaxometry technique to access and quantify spin diffusion in AFIs without external biases, advancing spin transport characterization.

Findings

Successfully measured spin diffusion constant of {}-Fe2O3

Detected frequency-dependent NV relaxation rates consistent with theoretical models

Showed NV centers can diagnose spin transport in high-frequency magnetic materials

Abstract

Antiferromagnetic insulators (AFIs) are of significant interest due to their potential to develop next-generation spintronic devices. One major effort in this emerging field is to harness AFIs for long-range spin information communication and storage. Here, we report a non-invasive method to optically access the intrinsic spin transport properties of an archetypical AFI {\alpha}-Fe2O3 via nitrogen-vacancy (NV) quantum spin sensors. By NV relaxometry measurements, we successfully detect the time-dependent fluctuations of the longitudinal spin density of {\alpha}-Fe2O3. The observed frequency dependence of the NV relaxation rate is in agreement with a theoretical model, from which an intrinsic spin diffusion constant of {\alpha}-Fe2O3 is experimentally measured in the absence of external spin biases. Our results highlight the significant opportunity offered by NV centers in diagnosing the underlying spin transport properties in a broad range of high-frequency magnetic materials, which are challenging to access by more conventional measurement techniques.