间隙原子氮对化合物RE_2Fe_(17)磁性的影响  

Effect of Interstitial Atom Nitrogen on Magnetic Properties of RE_2Fe_(17) Compounds

作　　者：董建敏[1] 李华[1] 孙美坤[1] 陈丽[1] 

机构地区：[1]山东大学物理与微电子学院,山东济南250100

出　　处：《中国稀土学报》2003年第4期406-409,共4页Journal of the Chinese Society of Rare Earths

基　　金：国家863计划(2002AA324050);山东省自然科学基金(Y2002D9)资助项目

摘　　要：用自旋极化的MS Xα方法计算了稀土 过渡族化合物Nd2Fe17Nx(x=0,3)中含哑铃Fe原子对的Fe8及含Nd和N原子的NdFe6和NdFe6N3原子簇的电子结构和磁矩。计算结果显示,在化合物Nd2Fe17中,Fe(c)和Fe(f)晶位间的分子轨道中,有3个奇宇称轨道呈现负交换耦合。通过比较α Fe的MS Xα计算结果,能够很好地说明RE2Fe17化合物居里温度较低的原因。在化合物Nd2Fe17N3中,Fe(c) Fe(f)晶位间分子轨道只剩下一个奇宇称轨道呈现弱的负交换耦合,通过比较N2Fe17和Nd2Fe17N3化合物Fe8原子簇的计算结果,能够很好地说明间隙原子M对化合物RE2Fe17Mx(M表示N,H或C)的居里温度产生影响的物理机制。对RE2Fe17型化合物中影响Fe Fe交换耦合的主要因素,本文也做了讨论。The electronic structure and atomic magnetic moments of cluster NdFe6 and Fe 8 with a dumbbell atom-pair in rare earth-transition element compounds Nd2Fe 17Nx (x=0, 3) were studied by spin-polarized MS-Xα metho d. The results show that (1) there are negative exchange couplings between Fe( c) and Fe(f) atoms in Nd2Fe17, which occur at their odd parity orbitals. Compared to the results of α-Fe calculated by MS-Xα method, the low Curie t emperature of compounds RE2Fe17 can be explained satisfactorily. (2) The r e is only one weaker negative exchange coupling orbital leaving in between Fe(c) and Fe(f) sites in Nd2Fe17N3. These results may be helpful for unders tanding the effect of interstitial atom M (η=N, H or C) in RE2Fe17M x on Curie temperature. The other key factors affecting the Fe-Fe exchange coupl ing in RE2Fe17 compounds were also discussed in this paper.

关 键 词：凝聚态物理 电子结构 Xα方法 原子磁矩 交换耦合 稀土 

分 类 号：TG113.25[金属学及工艺—物理冶金] O441.2[金属学及工艺—金属学]