Dy_2Fe_(17-x)Al_x化合物中的R──T交换耦合常数的计算

A Calculation about the Exchange Interaction Constant between the R-sublattice and the 3d-sublattice in Dy_2Fe_(17-x)Al_x Compounds

提出利用分子场近似结合中子衍射或Ｘ射线衍射的实验结果，计算Ｒ２Ｆｅ１７型稀土过 渡族化合物中的稀土磁矩与过渡族磁矩之间的交换耦合常数的方法．计算了 Ｄｙ２Ｆｅ１７－ｘＡｌｘ （ｘ＝２，３，４，５，６，７，８）化合物中的稀土磁矩与过渡族磁矩之间的交换耦合常数－ＪＲＴ／ｋ， 结果分别为７，７７ Ｋ，７．２７ Ｋ，７．３９ Ｋ，８．６２ Ｋ，８．６４Ｋ，９．５２ Ｋ，１０．３４ Ｋ．其中对ｘ＝５，６， ７，８的化合物计算结果与高场测量的实验值８．７７ Ｋ，９．２５ Ｋ，１０．１Ｋ，１０．９Ｋ符合得较好． 说明从分子场理论出发，利用Ｘ射线衍射或中子衍射的结果更细致地考虑一些替代的细 节，计算稀土过渡族化合物中的稀土（Ｒ）磁矩与过渡族（Ｔ）磁矩之间的交换耦合常数是 一种可取的方法．

A precise calculation of the exchange interaction constant JRT between the rare-end sub-lattice and the transition metal sub-lattice in R2Fe17-type compounds by the molecular-field model and the results of neutron diffraction is given. The calculated values, -JR,T/k, for Dy2Fe17-x Alx (x = 5, 6, 7 and 8) compounds are 8.62 K, 8.64 K, 9.52 K, and 10.34 K, respectively, they are in excellent agreement with the experimental values, -JK T/k of Dy2Fe17-x Alx (x = 5, 6, 7 and 8) compounds, which are 8.77 K, 9.25 K, 10.1 K, and 10.9 K, respectively.