Mixed-Type Skyrmions in Symmetric Pt/Co/Pt Multilayers at Room Temperature

We demonstrate the generation of mixed-type skyrmions (all are about 200 nm) that are primarily Bloch-type, hybrid-type, and a negligible amount of Neel-type in symmetric Pt/Co(1.55)/Pt multilayers at room temperature. The magnetic field dependence of skyrmion evolution is reversible. Brillouin light-scattering is used to quantitatively quantify the Dzyaloshinskii-Moriya interaction constant D in order to comprehend the mechanism. Interestingly, the D value is high enough to generate skyrmions in a symmetric sandwich structure. Micromagnetic simulations show that Neel-type skyrmions transform into Bloch-type skyrmions as the D value decreases. The interface-induced non-uniform D may be the cause to generate mixed-type skyrmions. This work broadens the flexibility to generate skyrmions by engineering skyrmion-based devices with nominally symmetric multilayers without the requirement of very large DMI.

Automated summary

This research demonstrates the generation of mixed-type skyrmions in symmetric Pt/Co(1.55)/Pt multilayers at room temperature, showing reversible evolution dependent on magnetic field. The high D value in this structure allows for the creation of skyrmions, with Neel-type skyrmions transforming into Bloch-type as D decreases. The non-uniform D at interfaces may play a role in generating mixed-type skyrmions.