Formation of Domains and magnetic Reversal in the canted Antiferromagnet α-Fe₂O₃

Antiferromagnets are at the forefront of research in spintronics and demonstrate high potential for revolutionizing memory technologies. Here, we study the canted antiferromagnet α-Fe₂O₃ using imaging based on x-ray magnetic linear dichroism (XMLD) and spin Hall magnetoresistance (SMR) measurements in α-Fe₂O₃/Pt Hall cross devices.

The domain structure forms a multi-domain state at zero field and depends strongly on the magnetic field. Combining angle-dependent SMR and XMLD measurements, we can find, that the internal destressing fields driving the formation of domains do not follow the hexagonal crystal symmetry of α-Fe₂O₃. Furthermore, the canting induces a weak ferromagnetic moment which lifts the degeneracy of the sublattices and consequently the orientation of the Néel vector with respect to the field resulting in hysteresis. The irreversibility upon switching the polarity of the field elucidates the formation of antiferromagnetic as well as ferromagnetic domain walls at low magnetic fields. These insights serve as a foundation for further studies of electrical and optical manipulation of the domain structure of canted antiferromagnets.