Method to suppress antiferromagnetic skyrmion deformation in high speed racetrack devices

A method for enhancing the stability of high speed antiferromagnetic skyrmions in racetrack devices is proposed and demonstrated numerically. Spatial modulation of the Dzyaloshinskii–Moriya interaction via a patterned top heavy metal gives rise to a strong confining potential. This counteracts skyrmion deformation perpendicular to the direction of propagation and the subsequent annihilation on contact with the racetrack’s horizontal boundaries. An achievable increase in the maximum driving current density of 135%, enabling higher velocities of 28%, is predicted. Furthermore, an extended saturating behavior of the mobility relation due to the imposed confinement is also found at large driving amplitudes, further enhancing skyrmion stability at high velocities.