Fig. 1: Resonant elastic x-ray scattering geometry and reciprocal space mapping.
a Illustration of the ω-2θ scattering geometry with ki and ks, the incident and scattered wave vectors, respectively. The REXS measurements were carried out with circularly polarized x-rays tuned to the Cu L3 absorption edge. The magnetic field B is applied along the x direction, i.e., in-plane, to allow for direct probing of the skyrmion strings, and z∥ [001] surface normal. The reciprocal space around the structural (001) reciprocal lattice point (red) is shown at diffraction condition, i.e., intersecting the Ewald sphere. The six magnetic satellites in the skyrmion phase (in green) lie in the (0, qy, qz) plane. b From 2θ and ω rocking scans, the scattered intensity in the (0, qy, qz) (out-of-plane cut) and (qx, qy,1) (in-plane cut) planes is reconstructed. The measured scattering contrast for c–e the modulated skyrmion phase is compared with the expected contrast for the (perfectly ordered) f–h pure skyrmion and i–k conical phases. In the first column, the magnetic structures are illustrated that lead to the scattering patterns in the (0, qy, qz) and (qx, qy,1) planes shown in the second and third column, respectively.
