Application of electron holography to ferroelectric study

Application of electron holography to the study of ferroelectric domain wall structures is presented in this paper. Polarization gradients within domain walls are important for the understanding of the extrinsic elastio-dielectric properties of ferroelectrics. Electron holographic studies of the local domain wall profiles provide essential input parameters for phenomenological theories of domain structure and of the macroscopic properties from the theories. The understanding of the phase transition is of direct importance of the domain formation and the domain wall movement. Also shown is distinct anomalous interference fringe pattern believed to be due to the charged point defect within the BaTiO₃ domain wall. Also because of the pinning effect of the point defect the domain size is about one third of the initial parent domain before heating. The electrostatic potential distribution around the charge centers is also displayed in detail.