Title: Current-density-modulated Antiferromagnetic Domain Switching Revealed by Optical Imaging in Pt/CoO(001) Bilayer

Abstract: Efficient control of antiferromagnetic (AFM) domain switching in thin films is vital for advancing antiferromagnet-based memory devices. In this study, we directly observed the current-driven switching process of CoO AFM domains in the Pt/CoO(001) bilayer by the magneto-optical birefringence effect. The observed critical current density for AFM domain switching remains nearly constant across varying CoO thicknesses, associated with the consistent switching polarity n $\perp$ j, suggesting the dominance of the thermomagnetoelastic effect, where and stand for Neel vector and current density vector, respectively. Further confirmation comes from a similar switching process with n $\perp$ j observed in the Pt/Al2O3/CoO sample, excluding the contribution of spin current injection. Remarkably, it was also surprisingly observed that the Neel vector can be further switched parallel to the current direction (n//j) at higher current density. Our findings not only enhance the understanding of current-driven AFM domain switching but also present new avenues for manipulating AFM domains.