Microscopic origin of the giant ferroelectric polarization in tetragonal-like BiFeO3
Zhang, J.X., Q. He, M. Trassin, W. Luo, D. Yi, M.D. Rossell, P. Yu, L. You, C.H. Wang, C.Y. Kuo, J.T. Heron, Z. Hu, R.J. Zeches, H.J. Lin, A. Tanaka, C.T. Chen, L.H. Tjeng, Y.-H. Chu, Ramamoorthy Ramesh
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.
Physical Review Letters
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