Rashba Torque Driven Domain Wall Motion in Magnetic Helices

TL;DR

This paper explores how the geometry of magnetic helices influences domain wall motion through Rashba torque, revealing new control mechanisms based on curvature and torsion effects in curvilinear magnetic systems.

Contribution

It introduces the impact of curvilinear geometry on exchange interaction, effective anisotropy, and Dzyaloshinskii--Moriya interaction in magnetic helices, enabling novel domain wall control methods.

Findings

Curvilinear effects induce effective anisotropy and Dzyaloshinskii--Moriya interactions.

Chiral symmetry breaking causes opposite domain wall motion in left- and right-handed helices.

Geometrical parameters like curvature and torsion directly influence magnetic interactions.

Abstract

Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange interaction of a magnetic helix results in an effective anisotropy term and Dzyaloshinskii--Moriya interaction with a complete set of Lifshitz invariants for a one-dimensional system. In contrast to their planar counterparts, the geometrically induced modifications of the static magnetic texture of the domain walls in magnetic helices offer unconventional means to control the wall dynamics relying on spin-orbit Rashba torque. The chiral symmetry breaking due to the Dzyaloshinskii-Moriya interaction leads to the opposite directions of the domain wall motion in left- or right-handed helices. Furthermore, for the magnetic helices, the emergent effective anisotropy term and Dzyaloshinskii-Moriya interaction can be attributed to the clear geometrical parameters like curvature and torsion offering intuitive understanding of the complex curvilinear effects in magnetism.