文章基本信息

标题：Revealing the flexoelectricity in the mixed-phase regions of epitaxial BiFeO3 thin films
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作者：Cheng-En Cheng ; Heng-Jui Liu ; Franco Dinelli 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep08091
语种：English
出版社：Springer Nature
摘要：Understanding the elastic response on the nanoscale phase boundaries of multiferroics is an essential issue in order to explain their exotic behaviour. Mixed-phase BiFeO₃ films, epitaxially grown on LaAlO₃ (001) substrates, have been investigated by means of scanning probe microscopy to characterize the elastic and piezoelectric responses in the mixed-phase region of rhombohedral-like monoclinic (M_I) and tilted tetragonal-like monoclinic (M_II,tilt) phases. Ultrasonic force microscopy reveal that the regions with low/high stiffness values topologically coincide with the M_I/M_II,tilt phases. X-ray diffraction strain analysis confirms that the M_I phase is more compliant than the M_II,tilt one. Significantly, the correlation between elastic modulation and piezoresponse across the mixed-phase regions manifests that the flexoelectric effect results in the enhancement of the piezoresponse at the phase boundaries and in the M_I regions. This accounts for the giant electromechanical effect in strained mixed-phase BiFeO₃ films.