Skyrmion Creation and Manipulation by Nano-Second Current Pulses.

H Y Yuan,X R Wang

doi:10.1038/srep22638

Abstract

Easy creation and manipulation of skyrmions is important in skyrmion based devices for data storage and information processing. We show that a nano-second current pulse alone is capable of creating/deleting and manipulating skyrmions in a spin valve with a perpendicularly magnetized free layer and broken chiral symmetry. Interestingly, for an in-plane magnetized fixed layer, the free layer changes from a single domain at zero current to a Neel wall at an intermediate current density. Reverse the current polarity, the Neel wall changes to its image inversion. A properly designed nano-second current pulse, that tends to convert one type of Neel walls to its image inversion, ends up to create a stable skyrmion without assistance of external fields. For a perpendicularly magnetized fixed layer, the skyrmion size can be effectively tuned by a current density.

Highlights

Easy creation and manipulation of skyrmions is apparently important in these applications
We show that a current can affect the states of a perpendicularly magnetized circular thin disk via spin-transfer torque (STT)
The spin valves naturally have the interfacial DMI in its free layer where one wants to create a skyrmion on-demand when the spacer layer is made of certain heavy metals that breaks inversion symmetry

Summary

Introduction

Easy creation and manipulation of skyrmions is apparently important in these applications. Under a nano-second current pulse whose STT tends to switch a Neel wall to its image inversion, a skyrmion can be created from and deleted to a single domain if the pulse heights and duration are properly controlled.

Results

Conclusion