中国物理B ›› 2011, Vol. 20 ›› Issue (10): 106101-106101.doi: 10.1088/1674-1056/20/10/106101

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Neutron diffraction study on composite compound Nd2Co7

杨育奇1, 李冠男1, 王通1, 高庆庆1, 李静波1, 刘广耀1, 骆军1, 饶光辉1, 黄清镇2   

  1. (1)Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (2)Centre for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
  • 收稿日期:2011-03-27 修回日期:2011-05-25 出版日期:2011-10-15 发布日期:2011-10-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 50631040) and the National Basic Research Program of China (Grants Nos. 2006CB601101 and 2006CB605101).

Neutron diffraction study on composite compound Nd2Co7

Yang Yu-Qi(杨育奇)a), Li Guan-Nan(李冠男) a)b), Wang Tong(王通)a), Huang Qing-Zhen(黄清镇)b), Gao Qing-Qing(高庆庆) a), Li Jing-Bo(李静波)a), Liu Guang-Yao(刘广耀)a), Luo Jun(骆军)a), and Rao Guang-Hui(饶光辉)a)†   

  1. a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; b Centre for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
  • Received:2011-03-27 Revised:2011-05-25 Online:2011-10-15 Published:2011-10-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 50631040) and the National Basic Research Program of China (Grants Nos. 2006CB601101 and 2006CB605101).

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摘要： The crystallographic and the magnetic structures of the composite compound Nd2Co7 at 300 K are investigated by a combined refinement of X-ray diffraction data and high-resolution neutron diffraction data. The compound crystallizes into a hexagonal Ce2Ni7-type structure and consists of alternately stacking MgZn2-type NdCo2 and CaCu5-type NdCo5 structural blocks along the c axis. A magnetic structure model with the moments of all atoms aligning along the c axis provides a satisfactory fitting to the neutron diffraction data and coincides with the easy magnetization direction revealed by the X-ray diffraction experiments on magnetically pre-aligned fine particles. The refinement results show that the derived atomic moments of the Co atoms vary in a range of 0.7 μB-1.1 μB and the atomic moment of Nd in the NdCo5 slab is close to the theoretical moment of a free trivalent Nd3+ ion, whereas the atomic moment of Nd in the NdCo2 slab is much smaller than the theoretical value for a free Nd3+ ion. The remarkable difference in the atomic moment of Nd atoms between different structural slabs at room temperature is explained in terms of the magnetic characteristics of the NdCo2 and NdCo5 compounds and the local chemical environments of the Nd atoms in different structural slabs of the Nd2Co7 compound.

Abstract: The crystallographic and the magnetic structures of the composite compound Nd2Co7 at 300 K are investigated by a combined refinement of X-ray diffraction data and high-resolution neutron diffraction data. The compound crystallizes into a hexagonal Ce2Ni7-type structure and consists of alternately stacking MgZn2-type NdCo2 and CaCu5-type NdCo5 structural blocks along the c axis. A magnetic structure model with the moments of all atoms aligning along the c axis provides a satisfactory fitting to the neutron diffraction data and coincides with the easy magnetization direction revealed by the X-ray diffraction experiments on magnetically pre-aligned fine particles. The refinement results show that the derived atomic moments of the Co atoms vary in a range of 0.7 μB-1.1 μB and the atomic moment of Nd in the NdCo5 slab is close to the theoretical moment of a free trivalent Nd3+ ion, whereas the atomic moment of Nd in the NdCo2 slab is much smaller than the theoretical value for a free Nd3+ ion. The remarkable difference in the atomic moment of Nd atoms between different structural slabs at room temperature is explained in terms of the magnetic characteristics of the NdCo2 and NdCo5 compounds and the local chemical environments of the Nd atoms in different structural slabs of the Nd2Co7 compound.

Key words: Nd2Co7, neutron powder diffraction, magnetic structure, crystal structure

中图分类号:  (X-ray diffraction)

  • 61.05.cp
61.05.F- (Neutron diffraction and scattering) 75.25.-j (Spin arrangements in magnetically ordered materials (including neutron And spin-polarized electron studies, synchrotron-source x-ray scattering, etc.))