Publication Type:Journal Article
Source:Physical Review Letters, Volume 107, Number 14 (2011)
Keywords:Experimental evidence, Ferroelectric polarization, ferroelectricity, First-principles calculation, Lone pair electrons, Oxygen octahedra, Polarization, room temperature, scanning transmission electron microscopy, transmission electron microscopy, X ray absorption spectroscopy
We report direct experimental evidence for a room-temperature, ∼130μC/cm2 ferroelectric polarization from the tetragonal-like BiFeO 3 phase. The physical origin of this remarkable enhancement of ferroelectric polarization has been investigated by a combination of x-ray absorption spectroscopy, scanning transmission electron microscopy, and first principles calculations. A large strain-induced Fe-ion displacement relative to the oxygen octahedra, combined with the contribution of Bi 6s lone pair electrons, is the mechanism driving the large ferroelectric polarization in this tetragonal-like phase. © 2011 American Physical Society.
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