Anomalous Magnetic Phase in an Undistorted Pyrochlore Oxide Cd2Os2O7 Induced by Geometrical Frustration
Anomalous Magnetic Phase in an Undistorted Pyrochlore Oxide Cd2Os2O7 Induced by Geometrical Frustration
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DOI：
10.1143/jpsj.76.063703
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发表时间：
2007-02
影响因子：
1.7
通讯作者：
A. Koda;R. Kadono;K. Ohishi;S. Saha;W. Higemoto;S. Yonezawa;Y. Muraoka;Z. Hiroi
中科院分区：
文献类型：
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作者：
A. Koda;R. Kadono;K. Ohishi;S. Saha;W. Higemoto;S. Yonezawa;Y. Muraoka;Z. Hiroi
报道了烧绿石氧化物Cd 2 Os 2 O 7的μ子自旋旋转/弛豫研究，该氧化物在TMI = 225 K时发生金属-绝缘体（MI）相变，但没有结构相变.结果表明，在MI跃迁以下存在强烈的自旋涨落（≥10 8 s-1），表明Os 5+离子的自旋受阻主要是由于几何自旋的作用.同时，进一步冷却后，在T_（SDW）~ 150 K以下，出现了不连续的无公度自旋密度波.这些观测结果强烈表明，在未畸变的烧绿石反铁磁体中发生了异常的磁跃迁和相关的局部自旋动力学变化。
We report on the muon spin rotation/relaxation study of a pyrochlore oxide, Cd 2 Os 2 O 7 , which exhibits a metal–insulator (MI) transition at T MI ≃225 K without structural phase transition. It reveals strong spin fluctuation (≥10 8 s -1 ) below the MI transition, suggesting a predominant role of geometrical spin frustration amongst Os 5+ ions. Meanwhile, upon further cooling, an incommensurate spin density wave discontinuously develops below T SDW ≃150 K. These observations strongly suggest the occurrence of an anomalous magnetic transition and associated change in the local spin dynamics in undistorted pyrochlore antiferromagnet.