Field-free spin-orbit torque switching from geometrical domain wall pinning

TL;DR

This paper demonstrates a novel method for field-free spin-orbit torque switching in magnetic microwires by exploiting geometrical domain wall pinning, enabling deterministic control without external magnetic fields.

Contribution

It introduces a new approach combining domain wall surface tension and spin-orbit effects to achieve deterministic, field-free switching in perpendicular magnetic memory devices.

Findings

Successful demonstration of field-free switching in microwires

Use of geometrical domain wall pinning for control

Potential for all-electric magnetic memory applications

Abstract

Spin-orbit torques, which utilize spin currents arising from the spin-orbit coupling, offer a novel method to electrically switch the magnetization with perpendicular anisotropy. However, the necessity of an external magnetic field to achieve a deterministic switching is an obstacle for realizing practical spin-orbit torque devices with all-electric operation. Here, we report a field-free spin-orbit torque switching by exploiting the domain wall motion in an anti-notched microwire with perpendicular anisotropy, which exhibits multi-domain states stabilized by the domain wall surface tension. The combination of spin-orbit torque, Dzyaloshinskii-Moriya interaction, and domain wall surface tension induced geometrical pinning allows a deterministic control of the domain wall and offers a novel method to achieve a field-free spin-orbit torque switching. Our work demonstrates the proof of concept of a perpendicular memory cell which can be readily adopted in a three-terminal magnetic memory.