Structural and magnetic properties of RTiNO2 (R=Ce, Pr, Nd) perovskite nitride oxides
Structural and magnetic properties of RTiNO2 (R=Ce, Pr, Nd) perovskite nitride oxides
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DOI：
10.1016/j.jssc.2015.01.023
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发表时间：
2015-03
影响因子：
3.3
通讯作者：
S. Porter;Zhenguo Huang;Zhenxiang Cheng;M. Avdeev;Zhixin Chen;S. Dou;P. Woodward
中科院分区：
文献类型：
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作者：
S. Porter;Zhenguo Huang;Zhenxiang Cheng;M. Avdeev;Zhixin Chen;S. Dou;P. Woodward
中子粉末衍射表明，cetino2和prtino2呈正交对称结晶(Ce:a=5.5580(5),b=7.8369(7), c=5.5830(4) Å；Pr:a=5.5468(5),b=7.8142（5), c=5.5514(5) Å），这是由于钛中心八面体的a - b+a倾斜造成的。仔细检查NPD数据，证实在这两种化合物中都没有长程阴离子顺序，而在电子衍射图中看到的明显的上层结构反射提供了短程阴离子顺序的证据。反磁化率图显示，theRTiNO2（R=Ce, Pr, Nd）化合物具有顺磁性，Weiss常数在−28 ~−42 K之间变化。rtino2 （R=Ce, Pr, Nd）的有效磁矩分别为2.43 μB， 3.63 μB和3.47 μB，与自由稀土离子的期望值一致。在150 K以下的cetino2和30 K以下的ndtino2的居里-威斯行为偏差是由磁各向异性、自旋-轨道耦合和晶体场效应驱动的。
Neutron powder diffraction indicates that CeTiNO2and PrTiNO2crystallize with orthorhombicPnmasymmetry (Ce:a=5.5580(5),b=7.8369(7), andc=5.5830(4) Å; Pr:a=5.5468(5),b=7.8142(5), andc=5.5514(5) Å) as a result ofa–b+a–tilting of the titanium-centered octahedra. Careful examination of the NPD data, confirms the absence of long range anion order in both compounds, while apparent superstructure reflections seen in electron diffraction patterns provide evidence for short range anion order. Inverse magnetic susceptibility plots reveal that theRTiNO2(R=Ce, Pr, Nd) compounds are paramagnetic with Weiss constants that vary from −28 to −42 K. Effective magnetic moments forRTiNO2(R=Ce, Pr, Nd) are 2.43 μB, 3.63 μB, and 3.47 μB, respectively, in line with values expected for free rare-earth ions. Deviations from Curie–Weiss behavior that occur below 150 K for CeTiNO2and below 30 K for NdTiNO2are driven by magnetic anisotropy, spin–orbit coupling, and crystal field effects.