Revealing the flexoelectricity in the mixed-phase regions of epitaxial BiFeO3 thin films

• DOI: 10.1038/srep08091
• Publication Date: 2015-01-28T10:26:18Z
• Authors: Cheng-En Cheng; Heng-Jui Liu; Franco Dinelli; Yi-Chun Chen; Chen-Shiung Chang; Forest Shih-Sen C...; Ying-Hao Chu
• Keywords: Piezoresponse force microscopy; Monoclinic crystal system; Tetragonal crystal system; Flexoelectricity; Ferroelasticity

Understanding the elastic response on nanoscale phase boundaries of multiferroics is an essential issue in order to explain their exotic behaviour. Mixed-phase BiFeO3 films, epitaxially grown LaAlO3 (001) substrates, have been investigated by means scanning probe microscopy characterize and piezoelectric responses mixed-phase region rhombohedral-like monoclinic (MI) tilted tetragonal-like (MII,tilt) phases. Ultrasonic force reveal that regions with low/high stiffness values topologically coincide MI/MII,tilt X-ray diffraction strain analysis confirms MI more compliant than MII,tilt one. Significantly, correlation between modulation piezoresponse across manifests flexoelectric effect results enhancement at regions. This accounts for giant electromechanical strained films.