Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures

TL;DR

This paper reports the first observation of stable chiral magnetic skyrmions at room temperature in ultrathin nanostructures without external magnetic fields, advancing nanoscale magnetic manipulation.

Contribution

It demonstrates room temperature, zero-field skyrmions in sputtered ultrathin films and elucidates their chiral structure and stability mechanisms through microscopy and simulations.

Findings

Stable skyrmions observed at room temperature and zero magnetic field

Chiral Ne9el structure confirmed by microscopy

Dzyaloshinskii-Moriya interaction strength explains skyrmion stability

Abstract

Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometer size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetisation at the nanoscale. To date, chiral skyrmion structures have been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films and under external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero applied magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral N\'eel internal structure which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.