Skyrmions in magnetic tunnel junctions

TL;DR

This paper demonstrates the controlled creation of skyrmions in magnetic tunnel junctions with DMI, proposing a multi-level device for data storage and neural network applications, and discusses their stability and detection.

Contribution

It introduces a method to nucleate and control skyrmions in MTJs using spin-polarized currents and stray fields, enabling multi-bit storage and neural network functionalities.

Findings

Skyrmions can be nucleated in MTJs with DMI using spin-polarized currents.

The size and stability of skyrmions are tunable via DMI strength and stray fields.

A multi-level tunneling magnetoresistance device for skyrmion-based storage is proposed.

Abstract

In this work, we demonstrate that skyrmions can be nucleated in the free layer of a magnetic tunnel junction (MTJ) with Dzyaloshinskii-Moriya interactions (DMI) by a spin-polarized current with the assistance of stray fields from the pinned layer. The size, stability and number of created skyrmions can be tuned by either the DMI strength or the stray field distribution. The interaction between the stray field and the DMI effective field is discussed. A device with multi-level tunneling magnetoresistance is proposed, which could pave the ways for skyrmion-MTJ-based multi-bit storage and artificial neural network computation. Our results may facilitate the efficient nucleation and electrical detection of skyrmions.