Spin-orbit torque induced dipole skyrmion motion at room temperature

TL;DR

This study demonstrates room-temperature control of dipole skyrmions in Fe/Gd multilayers using spin-orbit torques from heavy metal layers, enabling their manipulation for potential spintronic applications.

Contribution

It reveals how spin-orbit torques can deterministically move achiral dipole skyrmions at room temperature, a novel control mechanism in magnetic textures.

Findings

Skyrmions are stabilized at room temperature in Fe/Gd multilayers.

Spin-orbit torques can induce skyrmion motion at current densities around 10^8 A/m2.

Chiral Neel-like domain walls couple to spin-orbit torques, enabling skyrmion manipulation.

Abstract

We demonstrate deterministic control of dipole-field-stabilized skyrmions by means of spin-orbit torques arising from heavy transition-metal seed layers. Experiments are performed on amorphous Fe/Gd multilayers that are patterned into wires and exhibit stripe domains and dipole skyrmions at room temperature. We show that while the domain walls and skyrmions are achiral on average due to lack of Dzyaloshinskii-Moriya interactions, the N\'eel-like closure domain walls at each surface are chiral and can couple to spin-orbit torques. The current-induced domain evolutions are reported for different magnetic phases, including disordered stripe domains, coexisting stripes and dipole skyrmions and a closed packed dipole skyrmion lattice. The magnetic textures exhibit motion under current excitations with a current density ~10^8 A/m2. By comparing the motion resulting from magnetic spin textures in Fe/Gd films with different heavy transition-metal interfaces, we confirm spin currents can be used to manipulate achiral dipole skyrmions via spin-orbit torques.