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Room-Temperature Polar Ferromagnet ScFeO3Transformed from a High-Pressure Orthorhombic Perovskite Phase
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2014-10-21 , DOI: 10.1021/ja507958z
Takahiro Kawamoto 1 , Koji Fujita 1 , Ikuya Yamada 2, 3 , Tomohiko Matoba 1 , Sung Joo Kim 4 , Peng Gao 4 , Xiaoqing Pan 4 , Scott D. Findlay 5 , Cédric Tassel 6, 7 , Hiroshi Kageyama 6 , Andrew J. Studer 8 , James Hester 8 , Tetsuo Irifune 9 , Hirofumi Akamatsu 10 , Katsuhisa Tanaka 1
Affiliation  

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/cm(2). 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 Fe(3+) 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.

中文翻译:

室温极性铁磁体 ScFeO3 从高压正交钙钛矿相转化

多铁性材料一直是深入研究的主题,但合成那些在室温下同时呈现磁性和铁电极化的材料仍然是一个巨大的挑战。在这项工作中,我们成功地获得了 LiNbO3 型 ScFeO3,这是一种亚稳态相,由在 15 GPa 下高温下形成的斜方晶钙钛矿转化而来。同步加速器 X 射线和中子粉末衍射和高角度环形暗场扫描透射电子显微镜成像的组合结构分析表明,该化合物采用极性 R3c 对称性,三价 Sc 和 Fe 离子完全有序排列,形成高度扭曲ScO6 和 FeO6 八面体。计算出的沿六边形 c 轴的自发极化高达 100 μC/cm(2)。磁性研究表明,由于 Fe(3+) 自旋的倾斜 G 型反铁磁排序,LiNbO3 型 ScFeO3 是一种弱铁磁体,TN = 545 K,代表了第一个具有远高于室温的磁排序的 LiNbO3 型氧化物实例温度。本化合物和稀土正交钙钛矿 RFeO3(R = La-Lu 和 Y)的比较,所有这些都具有角共享的 FeO6 八面体网络,使我们能够找到 TN 和 Fe-O-Fe 之间的相关性键角,表明 A 位阳离子尺寸依赖的八面体倾斜通过 Fe-O-Fe 超交换相互作用主导了磁转变。这项工作提供了一种通用且通用的策略来创造在高温下铁电性和铁磁性共存的材料。
更新日期:2014-10-21
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