Crystal structures and magnetic properties of fluorite-related oxides Ln3NbO7 (Ln = lanthanides)
Crystal structures and magnetic properties of fluorite-related oxides Ln3NbO7 (Ln = lanthanides)
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DOI：
10.1016/j.jssc.2008.12.012
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发表时间：
2009-04-01
影响因子：
3.3
通讯作者：
Hinatsu, Yukio
中科院分区：
文献类型：
--
作者：
Doi, Yoshihiro;Harada, Yuka;Hinatsu, Yukio
报道了三元氧化物Ln(3)NbO(7) （Ln = La, Pr, Nd, Sm-Lu）的晶体结构和磁性能。粉末x射线衍射测量和Rietveld分析表明，它们具有与荧光石相关的空间群Pnma (Ln = La, Pr, Nd), C222(1) （Ln = Sm-Tb）或Fm-3m （Ln = Dy-Lu）。在1.8 ~ 400k范围内进行磁化率测量。Ln = Pr、Gd、Dy-Yb的Ln(3)NbO(7)化合物表现出居里-魏斯顺磁性，Sm3NbO7和Eu3NbO7表现出van Vleck顺磁性。另一方面，Nd3NbO7（0.6和2.7 K）和Tb3NbO7（2.0和3.2 K）均观察到两个磁异常。从比热测量结果来看，这些异常是由于Ln离子在两个不同的晶体位（8配位和7配位）上的反铁磁有序引起的。(C) 2008爱思唯尔公司版权所有。
Crystal structures and magnetic properties of the ternary oxides Ln(3)NbO(7) (Ln = La, Pr, Nd, Sm-Lu) are reported. Their powder X-ray diffraction measurements and Rietveld analyzes show that they have the fluorite-related structures with space group Pnma (Ln = La, Pr, Nd), C222(1) (Ln = Sm-Tb), or Fm-3m (Ln = Dy-Lu). Magnetic susceptibility measurements were carried out from 1.8 to 400 K. The Ln(3)NbO(7) compounds for Ln = Pr, Gd, Dy-Yb show Curie-Weiss paramagnetic behavior, and Sm3NbO7 and Eu3NbO7 show van Vleck paramagnetism. On the other hand, two magnetic anomalies were observed for both Nd3NbO7 (0.6 and 2.7 K) and Tb3NbO7 (2.0 and 3.2 K). From the results of specific heat measurements, it was found that these anomalies are due to the antiferromagnetic ordering of Ln ions in two different crystallographic sites (the 8-coordinated and 7-coordinated sites). (C) 2008 Elsevier Inc. All rights reserved.