新型稀土永磁材料Nd_2Fe_(17-x-y)Nb_xAl_y的中子衍射分析及磁性能研究

Neutron Diffraction Analysis and Magnetic Property Research of Novel Rare Earth Permanent Magnetic Material Nd_2Fe_(17-x-y)Nb_xAl_y

通过X射线衍射、中子衍射及磁测量等研究了Nb、Al双取代对Nd2Fe17-x-yNbxAly化合物结构和磁性能的协同影响。X射线衍射结果表明,Nd2Fe17-x-yNbxAly的晶胞体积几乎随Al含量的增加而线性增加,当Al含量相同时,Nb的加入引起晶胞体积的增大。中子衍射分析结果表明,Nb优先占据6c晶位,Al优先占据18h晶位。磁测量结果表明,0.0≤y≤3.0时,单取代的Nd2Fe17-yAly化合物的居里温度随Al含量的增加先升高后降低,但双取代的Nd2Fe16.5-yNb0.5Aly化合物的居里温度却随Al含量的增加而线性升高,这表明Nb、Al双取代对磁性能的改善会产生协同效应。

The combined effects of double substitution of Nb and Al for Fe on the crystallographic structure and magnetic properties of Nd2Fe17-x-yNbxAly compounds were investigated by means of X-ray diffraction,neutron diffraction and magnetic measurement.The Rietveld refinements of the diffraction data indicate that all the samples crystallize in the rhombohedral Th2Zn17-type structure with small impurities.The unit cell volumes of Nd2Fe17-x-yNbxAlyare all found to increase linearly with the increase of Al content and the unit cell volume of Nd2Fe16.5-yNb0.5Alyis larger than that of Nd2Fe17-yAly.The neutron diffraction indicates that Nb prefers to occupy 6c sites while Al prefers to occupy 18 h sites.The Curie temperature of Nd2Fe17-y Aly first increases and then decreases with the increase of Al content,while the Curie temperature of doubly substituted Nd2Fe16.5-yNb0.5Alyincrease linearly with 0.0≤y≤3.0,and it indicates the synergetic effect on the magnetic property.