Measuring the Formation Energy Barrier of Skyrmions in Zinc Substituted Cu${}_2$OSeO${}_3$

Abstract

We report small angle neutron scattering (SANS) measurements of the skyrmion lattice in (Cu${}_{0.976}$Zn${}_{0.024}$)${}_2$OSeO${}_3$ under the application of an electric field. These measurements show an expansion of the skyrmion lattice stability region with electric field similar to that seen in pristine Cu${}_2$OSeO${}_3$. Furthermore, using time-resolved SANS, we observe the slow formation of skyrmions after an electric or magnetic field is applied, which has not been observed in pristine Cu${}_2$OSeO${}_3$ crystals. The measured formation times are dramatically longer than the corresponding skyrmion destruction times after the external field is removed, and increase exponentially from 100~s at 52.5~K to 10,000~s at 51.5~K. This thermally activated behaviour indicates an energy barrier for skyrmion formation of 1.57(2)~eV, the size of which demonstrates the huge cost for creating these complex chiral objects.

8 pages, 8 figures

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Cited by in corpus (1)

• Pinning of Helimagnetic Phase Transitions in Zn-Substituted Skyrmion Host Cu${}_2$OSeO${}_3$