Thermal activation of ferroelectric switching

By applying the theory of thermally activated nucleation to the switching of ferroelectric domains, a method is developed to experimentally obtain the value of both the activation enthalpy, Delta H, and activation volume, V*, for the thermally activated process involved in ferroelectric switching. The method was applied to the switching of a soft lead zirconate titanate and values of Delta H =(0.16 +/- 0.02) eV and V*=(1.62 0.16) X 10(-25) m(3) were obtained at the coercive field. These values imply that the energy, Delta U, required for the formation of switching nuclei is mainly supplied by the work done by the electric field. A comparison of these values with those obtained from theoretical considerations suggests that the switching is achieved by the sideways expansion of nuclei formed at the domain boundaries in the form of low amplitude and long wavelength fluctuations of the domain walls.