Publication Type:Journal Article
Source:Advanced Functional Materials, Volume 19, Number 13, p.2053-2063 (2009)
Keywords:Bicrystal grain boundary, bismuth, Bismuth ferrites, Complex mechanisms, Depolarization fields, Domain nucleation, ferrite, Ferroelastic, Ferroelectric domains, Ferroelectric materials, ferroelectricity, Grain boundaries, Grain size and shape, hysteresis, Hysteresis loops, Interface charge, Materials properties, Mesoscopic, Microstructure engineering, nucleation, Optical switches, Phase interfaces, Phase-field modeling, Piezoresponse force microscopy, Polarization, polarization switching, quantitative analysis, Semiconducting bismuth compounds, Single defect, Spatially resolved, Superconducting materials, Switching, Tilt grain boundary, Wall energy
The deterministic mesoscopic mechanism of ferroelectric domain nucleation is probed at a single atomically-defined model defect: an artificially fabricated bicrystal grain boundary (GB) in an epitaxial bismuth ferrite film. Switching spectroscopy piezoresponse force microscopy (SS-PFM) is used to map the variation of local hysteresis loops at the GB and in its immediate vicinity. It is found that the the influence of the GB on nucleation results in a slight shift of the negative nucleation bias to larger voltages. The mesoscopic mechanisms of domain nucleation in the bulk and at the GB are studied in detail using phase-field modeling, elucidating the complex mechanisms governed by the interplay between ferroelectric and ferroelastic wall energies, depolarization fields, and interface charge. The combination of phase-field modeling and SS-PFM allows quantitative analysis of the mesoscopic mechanisms for polarization switching, and hence suggests a route for unraveling the mechanisms of polarization switching at a single defect level and ultimately optimizing materials properties through microstructure engineering. ©2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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