Observation of magnetic skyrmions in unpatterned symmetric multilayers at room temperature and zero magnetic field

TL;DR

This study demonstrates the spontaneous formation and stabilization of magnetic skyrmions at room temperature in unpatterned symmetric Pd/Co/Pd multilayers without external stimuli, advancing potential spintronic applications.

Contribution

It provides experimental evidence of skyrmions in symmetric multilayers at room temperature without external forces, and estimates the interfacial Dzyaloshinskii-Moriya interaction responsible for stabilization.

Findings

Skyrmions observed at room temperature without external stimuli.

Transition from worm-like domains to isolated skyrmions with decreasing ferromagnetic layer thickness.

Quantitative estimation of interfacial Dzyaloshinskii-Moriya interaction (iDMI).

Abstract

Magnetic skyrmions are promising candidates for the next generation of spintronic devices due to their small size and topologically protected structure. One challenge for using these magnetic states in applications lies on controlling the nucleation process and stabilization that usually requires an external force. Here, we report on the evidence of skyrmions in unpatterned symmetric Pd/Co/Pd multilayers at room temperature without prior application of neither electric current nor magnetic field. By decreasing the ferromagnetic interlayer thickness, the tuning of the physical properties across the ferromagnetic/non-magnetic interface gives rise to a transition from worm like domains patterns to isolated skyrmions as demonstrated by magnetic force microscopy. On the direct comparison of the measured and simulated skyrmions size, the quantitative interfacial Dzyaloshinskii-Moriya interaction (iDMI) was estimated, reveling that isolated skyrmions are just stabilized at zero magnetic field for low values of iDMI. Our findings provide new insights towards the use of stabilized skyrmions for room temperature devices in nominally symmetric multilayers.