Figure 4. Formation of the skyrmion crystal confirmed by small-angle neutron scattering (SANS).

(a) Temperature dependence of a.c.-magnetic susceptibility versus magnetic field measured in H || [110] for a single-crystalline piece of Co₈Zn₈Mn₄. Hysteresis on increasing and decreasing magnetic field is indicated by arrows. The magnetic field region sandwiched by dotted lines indicates the skyrmion crystal phase. (b,c) SANS images for a single-crystalline sample of Co₈Zn₈Mn₄ at 317 K obtained at H=0 and H=150 Oe, respectively. H and the incident neutron beam are parallel with each other and both along [110] direction. The horizontal and vertical axes of the SANS images correspond to the [001] and [1–10] crystal directions, respectively.