Room-temperature polar ferromagnet ScFeO3 transformed from a high-pressure orthorhombic perovskite phase
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Date
2014-10-21
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Publisher
American Chemical Society
Abstract
Multiferroic materials have been the subject of intense study, but it remains a great challenge to synthesize those presenting both magnetic and ferroelectric polarizations at room temperature. In this work, we have successfully obtained LiNbO3-type ScFeO3, a metastable phase converted from the orthorhombic perovskite formed under 15 GPa at elevated temperatures. A combined structure analysis by synchrotron X-ray and neutron powder diffraction and high-angle annular dark-field scanning transmission electron microscopy imaging reveals that this compound adopts the polar R3c symmetry with a fully ordered arrangement of trivalent Sc and Fe ions, forming highly distorted ScO6 and FeO6 octahedra. The calculated spontaneous polarization along the hexagonal c-axis is as large as 100 μC/cm2. The magnetic studies show that LiNbO3-type ScFeO3 is a weak ferromagnet with TN = 545 K due to a canted G-type antiferromagnetic ordering of Fe3+ spins, representing the first example of LiNbO3-type oxides with magnetic ordering far above room temperature. A comparison of the present compound and rare-earth orthorhombic perovskites RFeO3 (R = La-Lu and Y), all of which possess the corner-shared FeO6 octahedral network, allows us to find a correlation between TN and the Fe-O-Fe bond angle, indicating that the A-site cation-size-dependent octahedral tilting dominates the magnetic transition through the Fe-O-Fe superexchange interaction. This work provides a general and versatile strategy to create materials in which ferroelectricity and ferromagnetism coexist at high temperatures. © 2014 American Chemical Society.
Description
This paper presents a result of a joint research program carried out at Geodynamics Research Center, Ehime University. The SXRD and in situ XRD experiments were performed at on the BL02B2 beamline (Proposal Nos. 2010B1715 and 2013A1623) and the BL04B1 beamline (Proposal Nos. 2012B1334 and 2013B1662), respectively, at SPring-8 with the approval of JASRI. The NPD experiment was carried out on the diffractometer WOMBAT at ANSTO’s OPAL facility (Proposal No. P3177). Travel costs of T.K. and K.F. were supported by Institute for Solid State Physics, The University of Tokyo (Proposal No. a-03274), JAEA. We thank M. Fukuzumi for the ICP elemental analysis; J. Kim for the SXRD experiment at the BL02B2 beamline; M. Matsushita and H. Etani for the in situ SXRD observation at the BL04B1 beamline; B. Guillaume for the NPD experiment; T. Kuge, S. Hatamoto, and R. Kamakura for the SHG measurement and SEM observation; and I. Tanaka for the first-principles calculations. This research was partly supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (A) (Grant Nos. 25249090 and 25248016) and Scientific Research on Innovative Areas “Nano Informatics” (Grant No. 26106514). S.D.F. acknowledges support under the Discovery Projects funding scheme of the Australian Research Council (Project No. DP110101570).
Keywords
Temperature range, Polar regions, Ferromagnetism, Scandium, Iron, Perovskites, Cations, Oxides, Ions, Ambient temperature, Pressure range, Materials
Citation
Kawamoto, T., Fujita, K., Yamada, I., Matoba, T., Kim, S. J., Gao, P., Pan, X., Findlay, S. D., Tassel, C., Kageyama, H., Studer, A. J., Hester, J., Irifune, T., Akamatsu, H., & Tanaka, K. (2014). Room-temperature polar ferromagnet ScFeO3 transformed from a high-pressure orthorhombic perovskite phase. Journal of the American Chemical Society, 136(43), 15291-15299. doi:10.1021/ja507958z