Sub-100 nm Skyrmions at Zero Magnetic Field in Ir/Fe/Co/Pt Nanostructures

TL;DR

This study demonstrates the stabilization of sub-100 nm skyrmions at zero magnetic field in Ir/Fe/Co/Pt nanodots, revealing size tunability and confinement effects crucial for future nanoscale spintronic devices.

Contribution

It provides the first experimental evidence of zero-field sub-100 nm skyrmions in nanostructures and explores their size variation and stability under confinement.

Findings

Sub-100 nm skyrmions stabilized at zero magnetic field.

Skyrmion size varies with dot size and magnetic parameters.

Different stability states show distinct confinement behaviors.

Abstract

Magnetic skyrmions are chiral spin structures that have recently been observed at room temperature (RT) in multilayer thin films. Their topological stability should enable high scalability in confined geometries - a sought-after attribute for device applications. While umpteen theoretical predictions have been made regarding the phenomenology of sub-100 nm skyrmions confined in dots, in practice their formation in the absence of an external magnetic field and evolution with confinement remain to be established. Here we demonstrate the confinement-induced stabilization of sub-100 nm RT skyrmions at zero field (ZF) in Ir/Fe(x)/Co(y)/Pt nanodots over a wide range of magnetic and geometric parameters. The ZF skyrmion size can be as small as ~50 nm, and varies by a factor of 4 with dot size and magnetic parameters. Crucially, skyrmions with varying thermodynamic stability exhibit markedly different confinement phenomenologies. These results establish a comprehensive foundation for skyrmion phenomenology in nanostructures, and provide immediate directions for exploiting their properties in nanoscale devices.