IMF2017

Most magnetic multiferroics are actually antiferromagnets, including the archetypical BiFeO₃. The easy plane of antiferromagnetic domains is correlated to the polar direction and switching the ferroelectric polarization affects the AF sublattice vector. In addition, BiFeO₃ exhibits an incommensurate magnetic structure with a long range cycloid ordering of spins. Resorting to a non-invasive scanning magnetometer based on a single nitrogen-vacancy (NV) defect in diamond, we demonstrate the first real-space visualization of non-collinear antiferromagnetic order in a multiferroic thin film. Thanks to piezoresponse force microscopy, we highlight the correlation with the ferroelectric landscape and take advantage of the magnetoelectric coupling to manipulate the cycloid propagation direction with an electric field. Besides illustrating the unique potential of NV magnetometry for imaging complex antiferromagnetic order at the nanoscale, these results demonstrate how BiFeO₃ can be used as a versatile platform for the design of reconfigurable nanoscale spin textures.