Temperature dependence of the structure and energy of domain walls in a first-order ferroelectric

The structure and energy of domain walls of the first-order ferroelectric lead titanate PbTiO3 are determined as a function of temperature using quantitative weak-beam transmission electron microscopy, from room temperature up to the Curie temperature Tc=765K. The thickness of the domain walls increases from 2.8 to 10 nm, while the energy decreases from 53 to 7mJm-2. These results are analyzed in terms of the Landau-Devonshire theory.