Landau theory of interfacestress effect on the phase transition properties of ferroelectric films

Abstract

A coupling term between stress and polarization has been introduced into Landau free energy to describe the interface stress effect of a thin ferroelectric film. The stress is assumed decreases exponentially away from the interface. Profiles of polarization and susceptibility have obtained for both tensile and compressive stress. We find that the compressive stress can enhance the polarization near the interface and reduce the dielectric constant, and tensile can reduce the polarization and enhance the dielectric polarization near the interface. Temperature dependence of polarization and dielectric constant have also obtained The compressive interface stress can shift the Curie temperature to a higher temperature, even higher than the bulk Curie temperature, however tensile shifts the Curie temperature to a lower temperature.