Displacement-type ferroelectricity with off-center magnetic ions in perovskite Sr(1-x)Ba(x)MnO3.
We report a ferroelectric transition driven by the off-centering of magnetic Mn(4+) ions in antiferromagnetic Mott insulators Sr(1-x)Ba(x)MnO(3) with a perovskite structure. As x increases, the perovskite lattice shows the typical soft-mode dynamics, as revealed by the momentum-resolved inelastic x-ray scattering and far-infrared spectroscopy, and the ferroelectricity shows up for x ≥ 0.45. The observed polarization is comparable to that for a prototypical ferroelectric BaTiO(3). We further demonstrate that the magnetic order suppresses the ferroelectric lattice dilation by ∼70% and increases the soft-phonon energy by ∼50%, indicating the largest magnetoelectric effects yet attained.
Cross-Correlated Materials Research Group, Advanced Science Institute, RIKEN, Wako, Japan.
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Sakai
J
J
Fujioka
T
T
Fukuda
D
D
Okuyama
D
D
Hashizume
F
F
Kagawa
H
H
Nakao
Y
Y
Murakami
T
T
Arima
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Baron
Y
Y
Taguchi
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Tokura