Evidence for room-temperature multiferroicity in a compound with a giant axial ratio.
In the search for multiferroic materials magnetic compounds with a strongly elongated unit-cell (large axial ratio c/a) have been scrutinized intensely. However, none was hitherto proven to have a switchable polarization, an essential feature of ferroelectrics. Here, we provide evidence for the epitaxial stabilization of a monoclinic phase of BiFeO3 with a giant axial ratio (c/a=1.23) that is both ferroelectric and magnetic at room temperature. Surprisingly, and in contrast with previous theoretical predictions, the polarization does not increase dramatically with c/a. We discuss our results in terms of the competition between polar and antiferrodistortive instabilities and give perspectives for engineering multiferroic phases.
Béa
H
H
Unité Mixte de Physique CNRS/Thales, Campus de l'Ecole Polytechnique, 1 Av. A. Fresnel, 91767 Palaiseau, France.
Dupé
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B
Fusil
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S
Mattana
R
R
Jacquet
E
E
Warot-Fonrose
B
B
Wilhelm
F
F
Rogalev
A
A
Petit
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S
Cros
V
V
Anane
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A
Petroff
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F
Bouzehouane
K
K
Geneste
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G
Dkhil
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B
Lisenkov
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S
Ponomareva
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I
Bellaiche
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Bibes
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Barthélémy
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A