Orbital angular momentum and current-induced motion of a Skyrmion-textured domain wall in a ferromagnetic nanotube

TL;DR

This paper develops a theoretical framework for understanding how orbital angular momentum influences the current-driven motion of Skyrmion-textured domain walls in ferromagnetic nanotubes, revealing new insights into magnetic soliton dynamics.

Contribution

It introduces a theory linking orbital angular momentum of domain walls to Skyrmion charge and current-induced torque, highlighting a novel orbital degree of freedom in magnetic solitons.

Findings

Domain walls with Skyrmion charge possess finite orbital angular momentum.

Current exerts torque by transferring orbital angular momentum via emergent magnetic fields.

Orbital angular momentum plays a significant role in domain wall dynamics.

Abstract

We theoretically study the current-induced dynamics of a domain wall in a ferromagnetic nanotube by developing a theory for the orbital angular momentum of a domain wall and the current-induced torque on it. Specifically, a domain wall with nontrivial magnetization winding along the circumference is shown to possess finite orbital angular momentum, which is proportional to the product of its Skyrmion charge and position, and the current is shown to exert a torque changing the orbital angular momentum of the domain wall and thereby drives it. The current-induced torque is interpreted as the transfer of orbital angular momentum from electrons to the domain wall, which occurs due to the emergent magnetic field associated with the Skyrmion charge. Our results reveal a hitherto unrecognized utility of the orbital degree of freedom of magnetic solitons.