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arXiv · 1901.11508

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

M. N. Wilson·M. Crisanti·C. Barker·A. Štefančič·J. S. White·M. T. Birch·G. Balakrishnan·R. Cubitt·P. D. Hatton
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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.

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M. N. Wilson, M. Crisanti, C. Barker, A. Štefančič, J. S. White, M. T. Birch, G. Balakrishnan, R. Cubitt, P. D. Hatton. 2019-03-27. Measuring the Formation Energy Barrier of Skyrmions in Zinc Substituted Cu$_2$OSeO$_3$. https://doi.org/10.1103/physrevb.99.174421

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