Figure 2: Variations of spin texture with magnetic field in a 396-nm FeGe nanostripe at T=100 K.

(a–d) The different behaviour of spin helices with wave vectors Q || edge and Q edge in a magnetic field. (j–m) The corresponding enlarged region marked by the white boxes in the corresponding panels (a–d). Under the applied magnetic field, the spin helix with almost Q || edge transfers into skyrmions, whereas those with almost Q edge disappear directly without leaving skyrmions. (e–g) The collective movement of a skyrmion chain into the interior of the stripe with increasing magnetic field. (h–i) The transition of the isolated skyrmions to ferromagnetic spin textures with uniform edge state. The red arrows indicate the orientation of the magnetization around the edge. To show magnetic structure in FeGe nanostripe more clearly, all the images are tailored to remove the PtCx part. The defocus values used for Lorentz TEM imaging are −192 μm, 0, +192 μm. The scale bars in a–i and j–m are 500 and 100 nm, respectively.