Room Temperature Relaxometry of Single Nitrogen Vacancy Centers in Proximity to α-RuCl Nanoflakes.

Nitrogen vacancy (NV) center-based magnetometry has been proven to be a versatile sensor for various classes of magnetic materials in broad temperature and frequency ranges. Here, we use the longitudinal relaxation time of single NV centers to investigate the spin dynamics of nanometer-thin flakes of α-RuCl at room temperature. We observe a significant reduction in the in the presence of α-RuCl in the proximity of NVs, which we attribute to paramagnetic spin noise confined in the 2D hexagonal planes. Furthermore, the time exhibits a monotonic increase with an applied magnetic field. We associate this trend with the alteration of the spin and charge noise in α-RuCl under an external magnetic field. These findings suggest that the influence of the spin dynamics of α-RuCl on the of the NV center can be used to gain information about the material itself and the technique to be used on other 2D materials.