Isolated zero field sub-10 nm skyrmions in ultrathin Co films

TL;DR

This paper reports the discovery of stable, isolated sub-10 nm skyrmions at zero magnetic field in ultrathin Co films, achieved through specific material properties and interactions, advancing potential spintronic applications.

Contribution

It demonstrates the stabilization of zero-field, sub-10 nm skyrmions in ultrathin Co films, a significant step towards practical spintronic devices.

Findings

Skyrmions smaller than 5 nm coexisting with 1 nm domain walls.

Stability of skyrmions at zero magnetic field due to exchange frustration.

Detection of skyrmions using both spin-polarized and non-spin-polarized microscopy.

Abstract

Due to their exceptional topological and dynamical properties magnetic skyrmions - localized stable spin structures on the nanometre scale - show great promise for future spintronic applications. To become technologically competitive, isolated skyrmions with diameters below 10 nm that are stable at zero magnetic field and room temperature are desired. Despite finding skyrmions in a wide spectrum of materials, the quest for a material with these envisioned properties is still ongoing. Here we report zero field isolated skyrmions with diameters smaller than 5 nm coexisting with 1 nm thin domain walls in Rh/Co atomic bilayers on the Ir(111) surface. These spin structures are characterized by spin-polarized scanning tunnelling microscopy and can also be detected using non-spin-polarized tips due to a large non-collinear magnetoresistance. We demonstrate that sub-10 nm skyrmions are stabilised in these ferromagnetic Co films at zero field due to strong frustration of exchange interaction, together with Dzyaloshinskii-Moriya interaction and a large magnetocrystalline anisotropy.