Spin Torque Switching of Antiferromagnet*

Antiferromagnets with zero net magnetic moment, strong anti-interference and ultrafast switching speed have potential competitiveness in high-density data storage. Electrical switching of antiferromagnets is at the heart of their device application [1,2]. The antidamping torque-induced switching of Néel order is attained in a biaxial antiferromagnetic insulator NiO, which is manifested electrically via spin Hall magnetoresistance in NiO (100)/Pt bilayers [3]. The antiferromagnetic moments are switched towards the current direction, different from the vertical configuration in the fieldlike torque scenario (e.g., CuMnAs and Mn₂Au) [4,5]. On the other hand, electric field is used to switch the magnetic moment of Mn₂Au films grown on piezoelectric Pb(Mg_1/3Nb_2/3)_0.7Ti_0.3O₃ (PMN-PT) (011) substrates. When the electric field is swept, the easy axis of Mn₂Au is switched between [100] and [01-1] directions of PMN-PT (011) at room temperature, exhibiting a butterfly-like swithing feature. This feature indicates that the underlying mechanism is the electric field-induced ferroelastic strain. Such a transition of the easy axis leads to the change of threshold current for the field-like torque switching of Mn₂Au [6]. Electrical switching of antiferromagnetic moments pave the way for all-electrical writing and readout in antiferromagnetic spintronics.
[1] C. Song, et al. Nanotechnology 29, 112001 (2018)
[2] C. Song, et al. Prog. Mater. Sci. 87, 33 (2017)
[3] X. Z. Chen, et al. Phys. Rev. Lett. 120, 207204 (2018)
[4] P. Wadley, et al. Science 351, 587 (2016).
[5] X. F. Zhou et al. Phys. Rev. Appl. 9, 054028 (2018)
[6] X. Z. Chen, et al. To be submitted.