Kinetics of polarization switching in epitaxial BaTiO3

The kinetics of polarization switching in BaTiO$_{3}$ ferroelectric epitaxial thin films were studied using optical second harmonic generation (SHG). Epitaxial films were polydomain having both a and c variants. Upon application of a poling field the SHG signal increased according to the expression 1- exp-At$^{n}$ . The rise is attributed to a time dependent increase in the fraction of aligned domains. The kinetic exponent n was of the order of 0.2 indicating fractal dimensionality. The observed kinetics are consistent with a model developed to describe the electro-optic and dielectric relaxation response of polydomain thin films with a continuous distribution of domain sizes (Hoerman PRB 65 2002).