Figure 4: Topological prevention of domain wall annihilation by homochirality.

(a) Two 180° Néel DWs with the same chirality in down–up–down magnetized film, showing the magnetostatic charges. (b) A composite 360° Néel DW after application of a small out-of-plane magnetic field that drives them together. The magnetostatic charge prevents the two DWs from annihilating. (c) DW annihilation field as a function of D as calculated by micromagnetic simulations for different uniaxial anisotropy values. The inset illustrates the simulated magnetization profile of the up–down–up domain including two Néel walls squeezed together by an external field. Only a small section of a much larger film is depicted in this image.