Real-space imaging of non-collinear antiferromagnetic order with a single spin magnetometer*

Recently, Antiferromagnets have attracted considerable attention for next generation spintronic devices owing to their unique properties such as ultrafast magnetization dynamics and insensitivity to external magnetic field. To harness these functionalities, nanoscale control and imaging capabilities that are now routine for ferromagnets must be developed for antiferromagnetic (AF) systems. Here, using a non-invasive scanning nanomagnetometer based on a single nitrogen-vacancy (NV) defect in diamond, we demonstrate real-space visualization of non-collinear AF order in a magnetic thin film, at room temperature [1]. We image a 70 nm long spin cycloid in multiferroic BiFeO₃ thin film and also show electric field manipulation of the cycloid propagation direction. Besides highlighting the unique potential of NV magnetometry for imaging complex AF orders at the nanoscale, these results demonstrate how BiFeO₃ can be used as a versatile platform for the design of reconfigurable nanoscale spin textures. [1] I. Gross et al., Nature, 549, 252 (2017).