Room Temperature Relaxometry of Single Nitrogen Vacancy Centers in Proximity to α-RuCl 3 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 T 1 of single NV centers to investigate the spin dynamics of nanometer-thin flakes of α-RuCl 3 at room temperature. We observe a significant reduction in the T 1 in the presence of α-RuCl 3 in the proximity of NVs, which we attribute to paramagnetic spin noise confined in the 2D hexagonal planes. Furthermore, the T 1 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 3 under an external magnetic field. These findings suggest that the influence of the spin dynamics of α-RuCl 3 on the T 1 of the NV center can be used to gain information about the material itself and the technique to be used on other 2D materials.