Lifetime of coexisting sub-10 nm zero-field skyrmions and antiskyrmions

TL;DR

This paper predicts the coexistence of sub-10 nm skyrmions and antiskyrmions at zero magnetic field in a specific magnetic bilayer, with lifetimes exceeding an hour at low temperatures, highlighting potential for spintronic applications.

Contribution

It demonstrates the experimental feasibility and predicts long-lived coexistence of skyrmions and antiskyrmions in a real material system, extending prior model-based studies.

Findings

Skyrmions and antiskyrmions can coexist below 10 nm in a Rh/Co bilayer.

Lifetimes of these structures exceed one hour at temperatures up to 75 K.

Thermal activation influences creation and annihilation rates differently for skyrmions and antiskyrmions.

Abstract

Magnetic skyrmions have raised high hopes for future spintronic devices. For many applications it would be of great advantage to have more than one metastable particle-like texture available. The coexistence of skyrmions and antiskyrmions has been proposed in inversion symmetric magnets with exchange frustration. However, so far only model systems have been studied and the lifetime of coexisting metastable topological spin structures has not been obtained. Here, we predict that skyrmions and antiskyrmions with diameters below 10 nm can coexist at zero magnetic field in a Rh/Co bilayer on the Ir(111) surface -- an experimentally feasible system. We show that the lifetimes of metastable skyrmions and antiskyrmions in the ferromagnetic ground state are above one hour for temperatures up to 75 K and 48 K, respectively. The entropic contribution to the nucleation and annihilation rates differs for skyrmions and antiskyrmions. This opens the route to thermally activated creation of coexisting skyrmions and antiskyrmions in frustrated magnets with Dzyaloshinskii-Moriya interaction.