Current polarity-dependent manipulation of antiferromagnetic domains

Antiferromagnetic spintronics offers the potential for ultrahigh speed dynamics, stability against strong magnetic field perturbations, higher component packing density owing to the lack of stray fringing fields, as well as a wider material base and qualitatively new physical phenomena.
Tetragonal CuMnAs is a testbed system in which the antiferromagnetic order parameter can be switched reversibly using electrical currents (1). Previously, orthogonal in-plane current pulses were used to induce 90 degree rotations of antiferromagnetic domains in a multi-terminal geometry(2). This type of switching has now also been demonstrated in another antiferromagnet system with similar symmetry properties (4,5).
Here, we demonstrate a new mechanism by which antiferromagnetic domain walls in CuMnAs can be manipulated to realize stable and reproducible domain changes using only two electrical contacts. In this geometry, current polarity is reversed changing the sign of the current-induced fields. The resulting Néel spin orbit torque acts primarily on the domain wall. The reconfigurations are imaged using x-ray magnetic linear dichroism microscopy, and detected electrically. The switching by domain wall motion can occur at much lower current densities than coherent domain switching.
1)Jungwirth et al Nat. Nano. 11, 231–241 (2016).
2)Wadley et al. Science 351, 587-590 (2016).
4) S. Y. Bodnar et al. Nat. Commun. 9, 348 (2018)
5)Meinert et al arXiv:1706.06983
6) Wadley, P et al Nat. Nano.13, 362–365 (2018)