Crystal and Magnetic Structure of the Orthorhombic Perovskite YbMnO3
Crystal and Magnetic Structure of the Orthorhombic Perovskite YbMnO3
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DOI：
10.1021/cm052758t
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发表时间：
2006-03
影响因子：
8.6
通讯作者：
Yunhui Huang;H. Fjellvåg;M. Karppinen;B. Hauback;H. Yamauchi;J. Goodenough
中科院分区：
文献类型：
--
作者：
Yunhui Huang;H. Fjellvåg;M. Karppinen;B. Hauback;H. Yamauchi;J. Goodenough
钙钛矿多晶型的YbMnO 3已被重新审视。正交相是通过在5 GPa和1100 °C下高压退火，由六方溶胶-凝胶合成的YbMnO 3通过高压（HP）重构转变获得的。中子粉末衍射结果表明，HP晶体属于正交晶系，空间群为Pbnm。在298 K下，晶格参数a、B和c的精确值分别为5.2208（3）、5.8033（3）和7.3053（4）A。平均Mn−O−Mn角为141.9°，表明MnO 6八面体的强烈倾斜。磁化率测量表明Mn 3+自旋在TN = 43 K和Yb 3+自旋在4 K的反铁磁顺序。在9 K时，磁结构为Ay，有序矩为3.45（5）μB.磁化率在240 K和6−30 K以上的两个温度区服从居里-韦斯定律，χ = C/（T-θ）。在两个温度范围内，得到的有效顺磁矩μeff分别为6.37 μB和4.83 μB。关于Forme...
The perovskite polymorph of YbMnO3 has been revisited. The orthorhombic phase is obtained through a high-pressure (HP) reconstructive transformation from the hexagonal sol−gel-synthesized YbMnO3 by means of HP annealing at 5 GPa and 1100 °C. Neutron powder diffraction shows that the HP form crystallizes in the orthorhombic space group Pbnm. At 298 K, the refined values for lattice parameters a, b, and c are respectively 5.2208(3), 5.8033(3), and 7.3053(4) A. The average Mn−O−Mn angle is 141.9°, indicative of a strong tilting of the MnO6 octahedra. Magnetic susceptibility measurements indicate antiferromagnetic order of Mn3+ spins at TN = 43 K and of Yb3+ spins at 4 K. The magnetic structure is commensurate Ay with an ordered moment 3.45(5) μB at 9 K. The magnetic susceptibility obeys the Curie−Weiss law, χ = C/(T − θ), in two temperature regions, that is, above 240 K and 6−30 K. The obtained effective paramagnetic moments μeff are 6.37 μB and 4.83 μB for the two temperature ranges, respectively. The forme...