Real-space observation of a two-dimensional skyrmion crystal

Magnetoelectric skyrmions Skyrmions are stable topological textures with particle-like properties, a mathematical concept originally developed to describe nuclear particles, but which in the past decade has found application at all scales from microscopic to cosmological. Skyrmions have proved particularly useful to describe novel spin configurations in magnets, and last year the presence of skyrmions in the magnetic compounds MnSi and Fe1−xCoxSi was confirmed in neutron scattering experiments. Now Yu et al. present striking real-space images, using transmission electron microscopy, of a two-dimensional skyrmion lattice for the latter compound, in the form of a hexagonal arrangement of swirling spin structures. The lattice is shown to be stable for a wide range of temperatures and magnetic fields. The authors speculate that the observed nanometre-scale spin topology may lead to interesting new magnetoelectric effects.