Deterministic Field-free Switching of a Perpendicularly Magnetized Ferromagnetic Layer via the Joint Effects of Dzyaloshinskii-Moriya Interaction and Field-like Spin-orbit Torque: An Appraisal

TL;DR

This study uses micromagnetic simulations to demonstrate that the combined effects of Dzyaloshinskii-Moriya interaction and field-like spin-orbit torque can enable deterministic, field-free switching of perpendicular ferromagnetic layers, with implications for magnetic memory devices.

Contribution

It provides a detailed analysis of how DMI and FLT jointly influence field-free magnetization switching, highlighting conditions where FLT aids or hinders the process.

Findings

Deterministic switching is possible within specific DMI and current ranges.

FLT can both hinder and assist switching depending on conditions.

FLT extends the current density window for reliable switching.

Abstract

Field-free switching of perpendicularly magnetized ferromagnetic layer by spin orbit torque (SOT) from the spin Hall effect (SHE) is of great interest in the applications of magnetic memory devices. In this paper, we investigate the deterministic SOT switching through the joint effects of Dzyaloshinskii-Moriya Interaction (DMI) and field-like torque (FLT) by micromagnetic simulations. We confirmed that within a certain range of DMI values and charge current densities, it is possible to deterministically switch the magnetization without the assistance external magnetic field. We show that the FLT could play an adverse role in blocking and slowing down the magnetization switching under certain cases of DMI and charge current-driven field-free switching. However, in other cases, FLT can assist DMI on the deterministic field-free SOT switching. In addition, it is found that FLT can effectively expand the current density window for a deterministic field-free SOT switching in the presence of DMI.