Direct imaging of electrical switching of antiferromagnetic Néel order in α-Fe2 O3 epitaxial films

We report the direct observation of switching of the Néel vector of antiferromagnetic (AFM) domains in response to electrical pulses in micron-scale Pt/α-Fe2O3 Hall bars using photoemission electron microscopy. Current pulses lead to reversible and repeatable switching with the current direction determining the final state, consistent with Hall effect experiments that probe only the spatially averaged response. Current pulses also produce irreversible changes in domain structure, in and even outside the current path. In both cases only a fraction of the domains switch in response to pulses. Furthermore, the analysis of images taken with different x-ray polarizations shows that the AFM Néel order has an out-of-plane component in equilibrium that is important to consider in analyzing the switching data. These results show that - in addition to effects associated with spin-orbit torques from the Pt layer, which can produce reversible switching - changes in AFM order can be induced by purely thermal effects