Fig. 5: Néel wall chirality switching by BL nucleation and propagation.

a Schematic illustration of the wall chirality switching process (top view) under the IP field \({H}_{x}\). A, Initial state of a purely Néel wall oriented to the left. B, The wall with a BL nucleated under the driving force \({H}_{x}\). C, The switched region (blue) grown under \({H}_{x}\) by BL propagation. D, The wall becomes fully Néel to the right after the switched region expands across the entire wall. b An XMCD-PEEM image of two DWs with opposite spin orientations intersecting, where a 180° BL exists to maintain spin continuity. The spin orientation at the center of the DW is indicated by arrows. X-ray direction is aligned with the IP easy axis such that spin orientation at the center of DW gives maximum contrast (white contrast for parallel and dark contrast for antiparallel with the IP easy axis). The film image is 37 nm in thickness with a similar anisotropy landscape. Details of imaging conditions are discussed in the Supplementary. c Potential energy landscape for the BL nucleation process (A → D). The driving force from \({H}_{x}\) is denoted by 2\(\delta\). The energy barrier is denoted by \({E}_{a}\), and the lowering of the energy barrier by \({H}_{x}\) is denoted by \(\Delta {E}_{a}\).