Domain Structure and Reversal Dynamics of Magnetoelectric Antiferromagnets

The single domain state of magnetoelectric (ME) antiferromagnet like Cr₂O₃ can be switched isothermally at room temperature by simultaneous application of electric and magnetic fields (He, et al., Nat. Comm. 2010; Kosub, et al., Nat. Comm. 2017). However, studies pertaining to switching dynamics, especially in thin-film systems, have been limited.

Domain reversal involves switching between saturated single-domain states. This constraint does not limit the dynamic process of reversal, which can exhibit single or multi-domain switching mechanisms, or a mix of both. In general, the mechanism of domain reversal depends on material parameters like the exchange interaction and magnetic anisotropy, size and shape of the sample, structure of defects, and strength of the excitation including thermal fluctuations.

In this work, we theorize the spatial and temporal limits of ME-induced reversal of antiferromagnet domain for nucleation, domain wall propagation and coherent rotation. We also address the formation of non-trivial domain structures in equilibrium in thin film Cr₂O₃ (Wu, et al., Phys. Rev. Lett. 2011), despite the absence of magnetostatic interaction in the bulk.