论文部分内容阅读
通过X射线衍射及磁测量实验研究了Pr2 AlFe16-xMnx 化合物的结构与磁性 ,结果表明Pr2 AlFe16-xMnx 化合物具有Th2 Zn17型结构 ;随着锰替代量的增加 ,化合物的单胞体积呈现先小后大的非线性增加 ,分析表明该类化合物在其磁相变点附近存在较大的正的本征磁致伸缩现象。进一步对Pr2 AlFe13 Mn3 化合物进行的变温X射线衍射研究表明 ,该化合物在其居里点附近 (180～ 198K)存在负热膨胀现象 ,其热膨胀系数为 -3 .6× 10 -4/K。磁性测量表明随着锰含量的增加Pr2 AlFe16-xMnx 化合物的居里温度及自发磁化强度都急剧下降 ,对这些现象进行了解释。
The structure and magnetism of the Pr2AlFe16-xMnx compounds were investigated by X-ray diffraction and magnetic measurements. The results showed that the Pr2AlFe16-xMnx compounds have the structure of Th2Zn17. With the increase of manganese substitution, Large non-linear increase, the analysis shows that the compounds in the vicinity of its magnetic transition point there is a large positive intrinsic magnetostriction phenomenon. Further study of the temperature-programmed X-ray diffraction of the Pr2AlFe13Mn3 compound shows that the compound has a negative thermal expansion near its Curie point (180 ~ 198K) with a coefficient of thermal expansion of -3.6 × 10 -4 / K. Magnetic measurements show that the Curie temperature and spontaneous magnetization of Pr2AlFe16-xMnx compounds decrease sharply with the increase of Mn content, and these phenomena are explained.