Control of spin-orbit torque-driven domain nucleation through geometry in chirally coupled magnetic tracks

TL;DR

This paper explores how geometry and spin-orbit torques influence domain nucleation and control in chiral magnetic racetrack devices, advancing the design of domain-wall based logic circuits.

Contribution

It demonstrates tunable domain nucleation and selective domain wall injection in chiral magnetic tracks through device geometry and spin-orbit torque interplay.

Findings

Current-induced domain nucleation can be controlled by magnetic region orientation.

Selective domain wall injection depends on current density and device geometry.

Results enable design of multifunctional domain-wall logic circuits.

Abstract

The interfacial Dzyaloshinskii-Moriya interaction (DMI) can be exploited in magnetic thin films to realize lateral chirally coupled systems, providing a way to couple different sections of a magnetic racetrack and realize interconnected networks of magnetic logic gates. Here, we systematically investigate the interplay between spin-orbit torques, chiral coupling and the device design in domain wall racetracks. We show that the current-induced domain nucleation process can be tuned between single-domain nucleation and repeated nucleation of alternate domains by changing the orientation of an in-plane patterned magnetic region within an out-of-plane magnetic racetrack. Furthermore, by combining experiments and micromagnetic simulations, we show that the combination of damping-like and field-like spin-orbit torques with DMI results in selective domain wall injection in one of two arms of a Y-shaped devices depending on the current density. Such an element constitutes the basis of domain wall based demultiplexer, which is essential for distributing a single input to any one of the multiple outputs in logic circuits. Our results provide input for the design of reliable and multifunctional domain-wall circuits based on chirally coupled interfaces.