Study of domain reversal and its field-dependence in epitaxial BaTiO 3 thin films

Abstract

Polarization switching dynamics were investigated in ferroelectric BaTiO3 epitaxial layers. Using the linear electro-optic (EO) effect, the polarization switching was measured under pulse excitation. The switching is given by a simple analytical model where the EO response follows an extended exponential function in time in the form of [1-exp-(t/τ)Β], where τ and Β are kinetic parameters, which depend on field. The parameter τ has the value of several milliseconds and Β ranges from 0.2 to 0.3. The activation field α for domain growth was measured as a function of pulse width and field strength whereby the value of α decreases as the pulse width decreases. The activation field for the application of a pulse is higher than that upon the removal of the pulse. The difference is attributed to the existence of a depolarization field in the film in the direction of the external electric field. © 2010 American Institute of Physics.