The polarization and dielectric susceptibility of a ferroelectric bilayer film

A ferroelectric bilayer film consisting of two different ferroelectric constituent films with a transition layer within each constituent film and interfacial coupling between two materials is investigated based on the Ginzburg-Landau-Devonshire phenomenological theory. A parameter α, which describing the differences between physical properties of two constituent films is first introduced in our paper, and reflects a more realistic situation compared to the previous treatments assuming the same two constituent films. We study the polarization and dielectric susceptibility properties of the ferroelectric bilayer film with two different constituent films. The results present some interesting phenomena due to the introduction of parameter α.