Diameter-independent skyrmion Hall angle observed in chiral magnetic multilayers

Katharina Zeissler,Gavin Burnell,Gerrit Van Der Laan,Jörg Raabe,Richard Brearton,Christopher H Marrows,Sergey A Nikitov,Craig Barton,Jamie Massey,Mark C Rosamond,Edmund H Linfield,Alexandr V Sadovnikov,Alexandra J Huxtable,Thorsten Hesjedal,Simone Finizio

doi:10.1038/s41467-019-14232-9

Abstract

Magnetic skyrmions are topologically non-trivial nanoscale objects. Their topology, which originates in their chiral domain wall winding, governs their unique response to a motion-inducing force. When subjected to an electrical current, the chiral winding of the spin texture leads to a deflection of the skyrmion trajectory, characterised by an angle with respect to the applied force direction. This skyrmion Hall angle is predicted to be skyrmion diameter-dependent. In contrast, our experimental study finds that the skyrmion Hall angle is diameter-independent for skyrmions with diameters ranging from 35 to 825 nm. At an average velocity of 6 ± 1 ms−1, the average skyrmion Hall angle was measured to be 9° ± 2°. In fact, the skyrmion dynamics is dominated by the local energy landscape such as materials defects and the local magnetic configuration.

Highlights

7, Magnetic skyrmions are topologically non-trivial nanoscale objects. Their topology, which originates in their chiral domain wall winding, governs their unique response to a motioninducing force
The skyrmion dynamics is dominated by the local energy landscape such as materials defects and the local magnetic configuration
Under the influence of a driving force, a skyrmion will drift towards the wire edge, where the angle between the longitudinal and transverse motion is defined as the skyrmion Hall angle θSky 15

Summary

Introduction

Magnetic skyrmions are topologically non-trivial nanoscale objects. Their topology, which originates in their chiral domain wall winding, governs their unique response to a motioninducing force. A current density, i.e., driving force dependence of the skyrmion Hall angle, was reported in multilayer systems[20,25,26]. While it is clear that nanoscale variations in the magnetic parameters of devices lead to skyrmion deformation and a wide range of stable diameters[27,28], the influence of defects on motion[29] and the skyrmion Hall angle remains an active field of debate[20,23,26,27,30].

Results

Conclusion