Depolarization field effect on the properties of an asymmetric ferroelectric thin film with different electrodes

The Landau-type theory has been amended to study the physical properties of an Asymmetric Ferroelectric (AFE) thin film with different electrodes. A surface transition layer in one side of the film is introduced by a position-dependent Curie temperature to remarkably distinguish the other surface. We bring in a third power of polarization in the Landau free energy expression to describe the asymmetry due to two different surfaces. The effect of depolarization field is reflected by different electrodes and surface effects, because the compensation of charge is directly related to the depolarization field. The polarization, dielectric susceptibility, pyroelectric and properties of the AFE film under the action of depolarization field have been discussed. The results show that the general feature of AFE film is shift and asymmetry, while the function of depolarization field is to make the properties of AFE film tend to uniform and centrosymmetric.