Current-driven dynamics of antiferromagnetic skyrmions: from skyrmion Hall effects to hybrid inter-skyrmion scattering

Abstract

Antiferromagnetic (AFM) skyrmions have emerged as a highly promising avenue in the realm of spintronics, particularly for the development of advanced racetrack memory devices. A distinguishing feature of AFM skyrmions is the cancellation of their net topological charge, leading to an anticipated absence of the skyrmion Hall effect (SkHE). Here, we unveil that the latter is finite under the influence of spin-transfer torque, depending on the direction of the injected current impinging on intrinsic AFM skyrmions emerging in Cr/Pd/Fe trilayer on Ir(111) surface. Hinging on first principles combined with atomistic spin dynamics simulations, we identify the origin of the SkHE, which is due to the ellipticity of the skyrmions, and we uncover that FM skyrmions in the underlying Fe layer act as effective traps for AFM skyrmions, confining them and affecting their velocity. These findings hold significant promise for spintronic applications, the design of multi-purpose skyrmion tracks while advancing our understanding of AFM–FM skyrmion interactions and hybrid soliton dynamics in heterostructures.