Publication Type:Journal Article
Source:Journal of Materials Science, Volume 44, Number 19, p.5095-5101 (2009)
Keywords:Ambient environment, Defect cluster, defects, Domain nucleation, Electrostatic effect, Electrostatics, Ferroelectric films, Ferroelectric thin films, hysteresis, Hysteresis loops, Local defects, magnetic materials, manganese compounds, Piezoresponse, Semiconducting bismuth compounds, Single defect, Spatially resolved, Vacuum
Local piezoresponse hysteresis loops were systematically studied on the surface of ferroelectric thin films of BiFeO3 grown on SrRuO 3 and La0.7Sr0.3MnO3 electrodes and compared between ultrahigh vacuum and ambient environment. The loops on all the samples exhibited characteristic asymmetry manifested in the difference of the piezoresponse slope following local domain nucleation. Spatially resolved mapping has revealed that the asymmetry is strongly correlated with the random-field disorder inherent in the films and is not affected by the random-bond disorder component. The asymmetry thus originates from electrostatic disorder within the film, which allows using it as a unique signature of single defects or defect clusters. The electrostatic effects due to the measurement environment also contribute to the total asymmetry of the piezoresponse loop, albeit with a much smaller magnitude compared to local defects. © 2009 Springer Science+Business Media, LLC.
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