Image antiferromagnetic order switching using a scanning single-spin microscope*

Electrical switching of Néel order in an antiferromagnetic (AF) insulator is desirable as a basis for memory applications. Unlike electrically-driven switching of ferromagnetic order via spin-orbit torques, electrical switching of antiferromagnetic order remains poorly understood. Here we obtain nanoscale magnetic images of a canted AF, α-Fe₂O₃, using a home-built scanning nitrogen-vacancy (NV) center microscope. We study the change of the magnetic order of α-Fe₂O₃ induced by an external magnetic field and electric current. Our results show that the orientation of an in-plane 1-Tesla magnetic field influences the sample's magnetic state even after relaxation in a low field. We find that our sample has an overall in-plane uniaxial anisotropy, in contrast to the 3-fold magneto-crystalline anisotropy suggested in previous work. Our observations from the current-induced magnetic order switching experiment indicate that thermo-magnetoelastic effects alone are sufficient to induce magnetic switching in α-Fe₂O₃ and that spin-orbit torques may not be necessary.