Effect of defect induced nucleation and growth on switching behavior in ferroelectrics

The switching behavior in ferroelectrics has been simulated using a time-dependent-Ginzburg-Landau approach, incorporating the contributions of dipolar defects. The model also includes the coupling with elastic fields. The dipolar defects are simulated by an inhomogeneous electric field produced by these localized dipoles. Domain pattern evolution was simulated with the sudden application/removal of the external bias electric field. We found that due to defect induced nucleation, a multi-domain twinned state is stabilized when the external electric field is removed from a poled single domain state. On the application of field in the opposite direction, the twinned state can be switched to a single domain with reverse polarization. The associated switching current has also been calculated.