Flexoelectricity can play an important role in the reversal of the self-polarization direction in epitaxial BiFeO3 thin films. The flexoelectric and interfacial effects compete with each other to determine the self-polarization state. In Region I, the self-polarization is downward because the interfacial effect is more dominant than the flexoelectric effect. In Region II, the self-polarization is upward, because the flexoelectric effect becomes more dominant than the interfacial effect.
Keywords: BiFeO3 film; flexoelectric effect; self-polarization; strain gradient.
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.