Interplay between domain walls and magnetization curling induced by chemical modulations in cylindrical nanowires

TL;DR

This paper investigates how chemical modulations in cylindrical nanowires influence domain wall behavior, combining simulations and experiments to reveal mechanisms for controlling magnetic states for data storage.

Contribution

It demonstrates the interaction between domain walls and chemical modulations, showing how to control their motion and internal structure for potential memory applications.

Findings

Chemical modulations create a local energy well affecting domain wall motion.

Modulations can switch the internal circulation of domain walls.

Interaction involves long-range magnetostatic repulsion and local energy effects.

Abstract

Cylindrical magnetic nanowires have been proposed as a means of storing and processing information in a 3D medium, based on the motion of domain walls~(DWs). Introducing short chemical modulations in such wires would allow for reliable digital control of DWs. Here, we outline the intricate physics of the interaction of domain walls with modulations to control their motion, combining micromagnetic simulations and experimental evidence. This interaction combines a long-range moderate magnetostatic repulsion with a local energy well. The latter depends on the respective circulation sense of magnetization in the domain wall and modulation. We also show that a modulation has the ability to switch the internal circulation of a DW upon its propagation, thereby acting as a polarizing component and opening the possibility to exploit not only the position of walls, but also their internal structure.