Room temperature skyrmions in symmetric multilayers

Abstract

We experimentally demonstrate the generation of skyrmions (166 ± 42 nm) by controlling and modulating the skyrmion stability parameter κ through changing the Co layer thickness in the multilayer with repetitions of the symmetric Pt/Co/Pt trilayer. The magnetic field dependence of skyrmion evolution is reversible. Dzyaloshinskii–Moriya interaction constant D is quantitatively measured by Brillouin spectroscopy to understand the mechanism. Surprisingly, the D value is high enough to generate skyrmions in a symmetric sandwich structure although the value is smaller than that in an antisymmetric Pt/Co/Ta trilayer. The decreased D value with the increase in the Co layer thickness indicates that the Dzyaloshinskii–Moriya interaction is still contributed from the interfaces. This work broadens the flexibility to generate skyrmions by engineering skyrmion-based devices with nominally symmetric multilayer without the requirement of very large DMI.