All-optical control of antiferromagnetic domains via an inverse optical magnetoelectric effect

All-optical control of antiferromagnetic order is essential for realizing next-generation energy-efficient spintronic and high-speed memory applications. However, the optical writing of antiferromagnetic domains remains a fundamental challenge, because conventional opto-magnetic recording techniques rely on net magnetization, which is absent in antiferromagnets. In certain multiferroic antiferromagnets, the magnetic toroidal moment provides an additional degree of freedom through its inherent magnetoelectric coupling, which manifests as directional asymmetry in light propagation. Here we demonstrate the all-optical writing of antiferromagnetic domains using the inverse optical magnetoelectric effect in ferrotoroidic LiNiPO₄, driven solely by reversing the light propagation direction. This directional control arises from a strong coupling between the photon linear momentum and the magnetic toroidal moment, enabling non-volatile, deterministic and repeatable switching between time-reversed domains with arbitrary light polarization. Our findings establish an inverse optical magnetoelectric effect as a distinct mechanism for manipulating antiferromagnetic order, opening a new paradigm in opto-magnetism driven by photon momentum.