Magnetic skyrmions in noncentrosymmetric chiral magnets appear as an ordered lattice state, with the individual skyrmions measuring 3-100 nm. Though rarely reported, this is a decent length scale for carrying out soft x-ray scattering experiments. Here we present our recent studies on the magnetic characterization of chiral magnets, using resonant elastic x-ray scattering (REXS). We demonstrate the unique advantages of REXS that allow for the study of the microscopic structural information of skyrmions, inaccessible to other characterization techniques. First, we show that REXS is extremely surface sensitive [1], which allows for the probing of the multidomain skyrmion lattice state - a surface state of the skyrmion lattice [2]. Second, the variable probing area allows us to map out the real-space skyrmion domain structure [3], which is important for future applications. Third, we show that using circularly polarised light, REXS is capable to accurately determine the topological winding number of a skyrmion, rigorously following its mathematical definition [4]. This 'topology determination principle' is a general experimental strategy, applicable to a wide range of topologically ordered magnetic materials. Finally, we show REXS results on grown thin films, which unambiguously reveals their magnetic structure [5].

[1] S. L. Zhang et al., Phys. Rev. B 93, 214420 (2016).
[2] S. L. Zhang et al., Nano Lett. 16, 3285 (2016).
[3] S. L. Zhang et al., Appl. Phys. Lett. 109, 192406 (2016).
[4] S. L. Zhang, G. van der Laan, and T. Hesjedal, Nat. Comms. 8, 14619 (2017).
[5] S. L. Zhang et al., Sci. Rep. (2017). in press