Controlling the deformation of antiferromagnetic skyrmions in the high-velocity regime
KAUST DepartmentMaterial Science and Engineering Program
Physical Science and Engineering (PSE) Division
Spintronics Theory Group
Permanent link to this recordhttp://hdl.handle.net/10754/661355
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AbstractWhile antiferromagnetic skyrmions display appealing properties, their lateral expansion in the high-velocity regime hinders their potential for applications. In this work, we study the impact of spin Hall torque, spin transfer torque, and topological torque on the velocity-current relation of antiferromagnetic skyrmions with the aim of reducing this deformation. Using a combination of micromagnetic simulations and analytical derivations, we demonstrate that the lateral expansion of the antiferromagnetic skyrmion is reminiscent of the well-known Lorentz contraction identified in one-dimensional antiferromagnetic domain walls. We also show that in the flow regime the lateral expansion is accompanied by a progressive saturation of the skyrmion velocity when driven by spin Hall and topological torques. This saturation occurs at much smaller velocities when driven by the topological torque, while the lateral expansion is reduced, preventing the skyrmion size from diverging at large current densities. We extend this study toward synthetic antiferromagnets, where the weaker antiferromagnetic exchange leads to much larger lateral expansion at smaller current densities in all cases. This study suggests that a compromise must be made between skyrmion velocity and lateral expansion during the device design. In this respect, exploiting the topological torque could lead to better control of the skyrmion velocity in antiferromagnetic racetracks.
CitationSalimath, A., Zhuo, F., Tomasello, R., Finocchio, G., & Manchon, A. (2020). Controlling the deformation of antiferromagnetic skyrmions in the high-velocity regime. Physical Review B, 101(2). doi:10.1103/physrevb.101.024429
SponsorsThe authors acknowledge fruitful discussions with A. Abbout, C. A. Akosa, J.-V. Kim, and A. Thiaville. A.S., F.Z., and A.M. were supported by the King Abdullah University of Science and Technology (KAUST). R.T. and G.F. acknowledge the project ThunderSKY, funded by the Hellenic Foundation for Research and Innovation (HFRI) and the General Secretariat for Research and Technology (GSRT), under Grant Agreement No. 871.
PublisherAmerican Physical Society (APS)
JournalPhysical Review B