Selective multiple domain wall injection using spin-orbit torque

TL;DR

This paper presents a method for selectively injecting multiple domain walls in a magnetic nanowire using spin-orbit torque and external magnetic fields, enabling precise control over domain wall placement.

Contribution

The study introduces a simple, scalable scheme combining simulation and experiment for localized domain wall injection in ferromagnet/heavy metal bilayers.

Findings

Successful experimental demonstration of selective domain wall injection.

Simulation confirms scalability to multiple domains.

Method allows dense packing of magnetic domains.

Abstract

We demonstrate from both simulation and experiment a simple scheme for selective injection of multiple domain walls in a magnetic nanowire. The structure consists of a side-contact misaligned Hall bar made of ferromagnet/heavy metal bilayers. The combination of current-induced spin-orbit torque and an external magnetic field allows for the formation of localized domains with specific magnetization direction and length, thereby creating domain walls in predetermined locations. With the side contacts at two sides misaligned for a distance that is comparable to the contact width, it is possible to create densely packed domains by simply applying current between different pairs of side contacts. Simulation results show that the proposed scheme is scalable to a large number of domains with its dimension limited only by the domain wall width.