Effect of Electric Field on Surface and Center of Ferroelectric Film

Size, surface and temperature effects of first and second order phase transition of ferroelectric (FE) thin films have been discussed in detail in the literature. However, the reversal of polarization by an applied electric field in FE materials is an important phenomenon to the industrial and technological applications, and it is an active research area for experimentalists as well as for theories. The Tilley-Zeks model has well described the polarization profiles of FE thin films in the absence of electric field. Hence, we adopt the Tilley-Zeks model of free energy expression and a term P.E, which gives the energy due to the interaction of electric field E and polarization P, included in the free energy expression. We study the effects of electric field on polarization profile for second order FE thin films with different surface parameters for the case when the direction of electric field is along the direction of polarization (induced polarization phenomenon) and the case when the electric field is in opposite direction with the polarization (polarization reversal phenomenon). We have found that the switching time decreases with increasing the value of external electric field.