DIELECTRIC SUSCEPTIBILITY AND PYROELECTRIC DYNAMIC BEHAVIOR OF AN ASYMMETRIC FERROELECTRIC THIN FILM

Making use of the Landau-Khalatnikov dynamic equation, the dynamic behavior of dielectric susceptibility and pyroelectric coefficient of an asymmetric ferroelectric thin film described by a third power of polarization which stems from a surface transition layer has been studied for the first time. The influence of the surface transition layer, thickness of thin film, and frequency of electric field on susceptibility and pyroelectric coefficient of the system have been discussed. Our numerical data show that the surface transition layer makes the polarization distribution inhomogeneous and asymmetric. It is interesting to discover that the curves for susceptibility and pyroelectric coefficient vs electric field of this system present three asymmetrical peaks, which is different from the case of two same surface transition layers exhibiting two symmetric peaks. Moreover, on the negative electric field side, the outer peak of susceptibility and pyroelectric coefficient rises, while the inside peak drops with decreasing the size of system. As the frequency of the electric field increases, the three peaks of susceptibility and pyroelectric coefficient decrease and stretch out horizontally.