A Low-Temperature Order-Disorder Transition in a Cubic Cd6Yb Crystalline Approximant
A Low-Temperature Order-Disorder Transition in a Cubic Cd6Yb Crystalline Approximant
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立方Cd6Yb晶体近似中的低温有序-无序转变
DOI：
10.1143/jjap.41.l524
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发表时间：
2002
影响因子：
1.5
通讯作者：
Y. Ueda
中科院分区：
文献类型：
--
作者：
R. Tamura;Y. Murao;S. Takeuchi;M. Ichihara;M. Isobe;Y. Ueda
低温下的电阻率、比热和电子衍射实验明确地揭示了立方Cd_6 Yb晶体在110 K左右经历了可逆的有序-无序转变，它是最近发现的二十面体Cd_（5.7）Yb的1/1立方近似体。过渡是最有可能是由于四面体4Cd集群的取向有序的中心的十二面体笼;高于110 K的中心4Cd集群是无序的两个方向形成bcc结构（Im 3），而低于110 K，它是有序的混合B2（Pn 3）和B32（Fd 3 m）结构。
Electrical resistivity, specific heat and electron diffraction experiments at low temperatures unambiguously reveal that the cubic Cd6Yb crystal, which is a 1/1 cubic approximant to the recently discovered icosahedral Cd5.7Yb, undergoes a reversible order-disorder transition at about 110 K. The transition is most probably due to the orientational ordering of tetrahedral 4Cd clusters sitting at the center of dodecahedral cages; above 110 K the central 4Cd cluster is disordered over two orientations forming a bcc structure (Im3), whereas below 110 K it is ordered in mixed B2(Pn3) and B32(Fd3m) structures.