Tetrahedral Magnetic Order and the Metal-Insulator Transition in the Pyrochlore Lattice of Cd2Os2O7
Tetrahedral Magnetic Order and the Metal-Insulator Transition in the Pyrochlore Lattice of Cd2Os2O7
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DOI：
10.1103/physrevlett.108.247205
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发表时间：
2012-06-13
影响因子：
8.6
通讯作者：
Hiroi, Z.
中科院分区：
文献类型：
--
作者：
Yamaura, J.;Ohgushi, K.;Hiroi, Z.
Cd_2Os_2O_7在227 K时表现出一种特殊的金属-绝缘体相变，在挫挫烧绿石晶格中具有磁有序性，但其有序态的磁结构和相变起源尚未揭示。我们观察到一个相称的磁峰共振X射线散射在高品质的单晶。X射线衍射和拉曼散射实验证实了该跃迁不伴有任何空间对称性破缺。我们提出了一个非共线的全进全出自旋排列的四面体网络的Os原子。基于此，我们认为，过渡是不是由斯莱特机制，如前所述，但由一个替代机制有关的形成特定的四面体磁序烧绿石晶格在存在强的自旋轨道相互作用。
Cd2Os2O7 shows a peculiar metal-insulator transition at 227 K with magnetic ordering in a frustrated pyrochlore lattice, but its magnetic structure in the ordered state and the transition origin are yet uncovered. We observed a commensurate magnetic peak by resonant x-ray scattering in a high-quality single crystal. X-ray diffraction and Raman scattering experiments confirmed that the transition is not accompanied with any spatial symmetry breaking. We propose a noncollinear all-in-all-out spin arrangement on the tetrahedral network made of Os atoms. Based on this we suggest that the transition is not caused by the Slater mechanism as believed earlier but by an alternative mechanism related to the formation of the specific tetrahedral magnetic order on the pyrochlore lattice in the presence of strong spin-orbit interactions.