Spin-induced multiferroicity in the binary perovskite manganite Mn2O3
J. Cong, K. Zhai, Y. Chai, D. Shang, D. D. Khalyavin, R. D. Johnson, D. P. Kozlenko, S. E. Kichanov, A. M. Abakumov, A. A. Tsirlin, L. Dubrovinsky, X. Xu, Z. Sheng, S. V. Ovsyannikov, and Y. Sun
Nature Communications 9, 2996 (2018), https://doi.org/10.1038/s41467-018-05296-0
At ambient conditions, bixbyite mineral, (Mn,Fe)2O3 crystallizes in a cubic bixbyite-type structure. Under high pressures, corresponding to those in the Upper Mantle, iron-free bixbyite Mn2O3 was found to transform into a double-perovskite-type lattice, comprising the Mn ions in three oxidation states (+2, +3, +4), thereby leading to its electronic formula, as follows: Mn2+(Mn3+)3(Mn3.25+)4O12.
We synthesized samples of this Mn2O3 perovskite at high-pressure high-temperature (HP-HT) conditions and examined their physical properties. We found that this unusual binary perovskite exhibits magnetically-driven ferroelectricity and a pronounced magnetoelectric effect at low temperatures. Neutron powder diffraction revealed two intricate antiferromagnetic structures below 100 K, driven by a strong interplay between spin, charge and orbital degrees of freedom. Hence, we experimentally established that the perovskite-type Mn2O3 turns to be a multifferoic at low temperature below 50 K. Thus, on the example of Mn2O3, we demonstrated the potential of binary perovskite oxides of transition metals for creating materials with highly promising electric and magnetic properties.
Left: Unit cell of the crystal lattice of the perovskite-type Mn2O3. Right: The electric polarization as a function of temperature measured with a poling electric field of 0.4 MV/m at zero magnetic field.