Bi-stability of magnetic skyrmions in ultrathin multilayer nanodots induced by magnetostatic interaction

TL;DR

This paper demonstrates that magnetostatic interactions in ultrathin multilayer nanodots can induce bi-stability of magnetic skyrmions, stabilizing two different skyrmion sizes under certain conditions, which is significant for magnetic storage applications.

Contribution

The study reveals that magnetostatic energy can stabilize large-radius skyrmions and induce bi-stability in ultrathin multilayer nanodots, expanding understanding of skyrmion stability mechanisms.

Findings

Magnetostatic energy influences skyrmion stability in nanodots.

Bi-stability of skyrmions with two radii observed.

Bi-stability occurs at specific DMI strengths and layer thicknesses.

Abstract

We report the results of simulations of magnetic skyrmion stability in ultrathin magnetic multilayer nanodots with interfacial Dzyaloshinskii-Moriya exchange interaction (DMI). We found that in presence of the lateral confinement the magnetostatic energy significantly influences the skyrmion stability and leads to stabilization of large radius skyrmion even at low values of the DMI strength, in addition to small radius skyrmion stabilized by DMI. In particular, stabilization of the skyrmion state with two different radii (bi-stability) is found in dipolarly-coupled (Pt/Co/Ir)$_{n}$ circular nanodots with the number of repeats of the unit cell $n$ = 3 and 5. The bi-stability range is located at the DMI strength of 0.9-1.1 mJ/m$^2$ or at the total Co-layer thickness of 2.2-2.6 nm.