We report the study of the skyrmion state near the surface of ${\mathrm{Cu}}_2{\mathrm{OSeO}}_3$ using soft resonant elastic x-ray scattering (REXS) at the Cu $L_3$ edge. Within the lateral sampling area of $200\times 200\mu {\mathrm{m}}^2$, we found a long-range-ordered skyrmion lattice phase as well as the formation of skyrmion domains via the multiple splitting of the diffraction spots. In a recent REXS study of the skyrmion phase of ${\mathrm{Cu}}_2{\mathrm{OSeO}}_3$ [M. C. Langner, S. Roy, S. Mishra, J. Lee, X. Shi, M. Hossain, Y.-D. Chuang, S. Seki, Y. Tokura, S. Kevan, and R. Schoenlein, Phys. Rev. Lett. 112, 167202 (2014)], the authors reported the observation of the unexpected existence of two distinct skyrmion sublattices that arise from inequivalent Cu sites, and that the rotation and superposition of the two periodic structures lead to a moiré pattern. However, we find no energy splitting of the Cu peak in x-ray-absorption measurements and, instead, discuss alternative origins of the peak splitting. In particular, we find that for magnetic field directions deviating from the major cubic axes a multidomain skyrmion lattice state is obtained, which consistently explains the splitting of the magnetic spots into two—and more—peaks.

• Received 1 October 2015
• Revised 27 April 2016

DOI:https://doi.org/10.1103/PhysRevB.93.214420