Identification of Néel vector orientation in antiferromagnetic domains switched by currents in NiO/Pt thin films

Abstract

Understanding the electrical manipulation of the antiferromagnetic order is a crucial aspect to enable the design of antiferromagnetic devices working at THz frequencies. Focusing on collinear insulating antiferromagnetic NiO/Pt thin films as a materials platform, we identify the crystallographic orientation of the domains that can be switched by currents and quantify the Neel-vector direction changes. We demonstrate electrical switching between different T domains by current pulses, finding that the Neel-vector orientation in these domains is along [+/- 5 +/- 5 19], different compared to the bulk (112) directions. The final state of the in-plane component of the Neel vector nIP after switching by current pulses j along the [1 +/- 1 0] directions is nIP 11 j. By comparing the observed Neel-vector orientation and the strain in the thin films, assuming that this variation arises solely from magnetoelastic effects, we quantify the order of magnitude of the magnetoelastic coupling coefficient as b0 + 2b1 = 3 x 107J/m3. This information is key for the understanding of current-induced switching in antiferromagnets and for the design and use of such devices as active elements in spintronic devices.