Toeno van der Sar's group uses NV-centre diamond magnetometry to study correlated spin dynamics and electric currents in magnetic and 2D materials. Research directions: (1) scanning NV magnetometry of topological magnets, 2D magnetic materials (CrI3, Fe3GeTe2), and superconductors; (2) spin-wave (magnon) spectroscopy in magnetic thin films using NV sensors; (3) widefield NV imaging of biological samples and materials. The group develops both NV scanning probes and widefield NV ensembles for nanoscale spatial mapping of magnetic phenomena.