Room Temperature Relaxometry of Single Nitrogen Vacancy Centers in Proximity to -RuCl₃ 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 alpha-RuCl3 at room temperature. We observe a significant reduction in the T-1 in the presence of alpha-RuCl3 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 alpha-RuCl3 under an external magnetic field. These findings suggest that the influence of the spin dynamics of alpha-RuCl3 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.