fig4

Figure 4. (A) An ADF-STEM image of a head-to-head 180° domain wall in a (010) FIB-prepared lamella. Large and bright atoms columns are Bi, and smaller ones are Fe. O atoms are not visible. (B) Quiver plot of local -δ_FB vectors, indicating the magnitude and direction of polarisation in each unit cell. (C) Ideal (010) projection of BiFeO₃; Bi atoms are red, Fe blue, and O grey. The direction of the -δ_FB vector is also shown. (D-G) core-loss EELS data: image size is 1.32 × 3.13 nm. (D) HAADF-STEM; (E) an element map of Fe; (F) an element map of O; (G) a composite of ADF (red) and Fe (green).