Ferroelectric domain walls in BaTiO₃: Structural wall model interpreting fingerprints in XRPD diagrams

Abstract

Accurate analyses of X-ray diffraction patterns of micrometric BaTiO₃ grains has shown that 90° domain wall is not a single twin (101) plane but a few nanometers wide region where the twinning crystallographic discontinuity could be accommodated by atom plane translations. A structural model of the 90 ° domain wall based on curved (001) and (100) planes is proposed. Its theoretical diffraction treatment is developed. The good agreement between experimental fingerprints and theoretical line profiles allows to propose a wall thickness of around 140 Å for micrometric BaTiO₃ grains whereas their domain thickness is of the order of 0.1μm.