Interfacial effects on the polarization of $BiFe{O}_3$ films

By considering an interfacial layer between the electrode and the $BiFe{O}_3$($BFO$) layer, the polarization and the hysteresis behavior of $BFO$ film are simulated. It is found that the non-ferroelectric interface will increase the coercive field, and remarkably suppress the polarization of the ultrathin film under low applied fields. Due to the competition between the interfacial effect and the internal compressive stress, the maximum polarization on the P-E loop of a $BFO$ film can be independent on the film thickness under an adequate applied field.