3D Reconstruction of Sawtooth 180° Tail‐to‐Tail Domain Walls in Single Crystal BiFeO₃

Abstract Previous studies of single crystal BiFeO 3 have found a dense domain structure with alternating sawtooth and flat domain walls (DWs). The nature of these domains and their 3D structure has remained elusive to date. Herein, several sections taken at different orientations are used to examine the structure in detail, concentrating here on the sawtooth DWs using diffraction contrast transmission electron microscopy, electron diffraction, and aberration‐corrected scanning transmission electron microscopy (STEM). All DWs are found to be 180° type; the flat walls have head‐to‐head polarity while the sawtooth DWs are tail‐to‐tail with peaks elongated along the polar [111] axis, formed by neutral () DW facets and slightly charged facets with orientations close to () and (). The neutral DW facets are Ising type and very abrupt, while the charged DW facets have mixed Néel/Bloch/Ising character with a chiral nature and a width of about 2 nm.