Large interfacial spin-orbit torques in layered antiferromagnetic insulator NiPS₃/ferromagnet bilayers

Finding efficient ways of manipulating magnetic bits is one of the core goals in spintronic research. Electrically-generated spin-orbit torques (SOTs) are good candidates for this and the search for materials capable of generating highly-efficient SOTs has gained a lot of traction in the recent years. While antiferromagnet/ferromagnet bilayer structures have been employed extensively for passive applications, e.g. by using exchange bias fields, their active properties are not yet widely employed. Here we show the presence of large interfacial SOTs in bilayer of a ferromagnet and the two-dimensional layered antiferromagnetic insulator NiPS3. We observe a large in-plane damping-like interfacial torque, showing a torque conductivity of σDL≈1×105(ℏ2e)/(Ωm) even at room temperature, comparable to the best devices reported in the literature for standard heavy-metal-based and topological insulators-based devices. Additionally, our devices also show an out-of-plane field-like torque arising from the NiPS3/ferromagnet interface, further indicating the presence of an interfacial spin-orbit coupling in our structures. Temperature-dependent measurements reveal an increase of the SOTs with a decreasing temperature below the Néel temperature of NiPS3 (TN≈170K), pointing to a possible effect of the magnetic ordering on our measured SOTs. Our findings show the potential of antiferromagnetic insulators and two-dimensional materials for future spintronic applications.