Investigation of the Flexoelectric Coupling Effect on the 180° Domain Wall Structure and Interaction with Defects

A new theory for 180° domain wall in ferroelectric perovskite material is presented in this work. The effect of flexoelectric coupling on the domain structure is analyzed. We show that the 180° domain wall has a mixed character of Ising and Bloch type wall and that the polarization perpendicular to the domain wall is not zero though it is very small compared to the spontaneous polarization in the case of tetragonal Barium Titanate. Finally, we present the effect of the new finding on the domain wall interaction with defects in the material.