Extended Data Fig. 8: Lorentz TEM images showing the nucleation of magnetic antiskyrmions.

The initial state of the system was different from that presented in Fig. 3a. The images were recorded over-focus in increasing perpendicular magnetic fields. The magnitude of the field is indicated above each image. a and b are identical. Lines in a mark domain walls, similar to those in Fig. 3a. Red circles mark antiskyrmions, which collapse at 224 mT (see h and i). The two skyrmions labeled in h annihilate with two antiskyrmions with increasing field (see j). j shows a skyrmion-antiskyrmion pair, which annihilates with increasing field at 243 mT (see k). The antiskyrmions collapse at a field of 259 mT (see l). The defocus distance is 600 μm.