稀土过渡金属CaCu_5型衍生化合物结构的原子级模拟  

Atomistic Simulation of Rare Earth-Transition Intermetallic Compounds Derived from CaCu_5 Type

作　　者：陈难先[1] 吕曜[1] 申江[1] 

机构地区：[1]清华大学物理系

出　　处：《中国稀土学报》2004年第1期34-39,共6页Journal of the Chinese Society of Rare Earths

摘　　要：稀土过渡族金属化合物是功能材料研究领域的重要对象。本文综述了CaCu5衍生型稀土过渡金属化合物Rn-mM5n+2m结构和变换关系的传统内容、含义,以及在应用中的有效性和局限性。从原子间相互作用势出发,通过能量最小化对5类二元本征结构SmFe5,Sm2Fe17(H),Sm2Fe17(R),SmFe12(t),Sm3Fe29的空间群及晶格参数进行了计算,并由此确定了这5类结构间的变换矩阵,与传统矩阵变换关系作了对照,分析了它们相近和相异的原因。讨论了第三元素Cr,Ti对Sm3Fe29结构的稳定作用,以及对晶体几何参数及X光谱的影响,这都是传统矩阵变换反映不了的。The rare earth(R)-transition metal(M) compounds are important subjects of new functional materials. In this paper, first we review the transformation relations between R-M compounds (R_(n-m)M_(5n+2m)) derived from CaCu_5 type structure, and discuss their validity and limitations. Then we calculate the lattice parameters and crystal structures of five binary compounds, SmFe_5, Sm_2Fe_(17)(H), Sm_2Fe_(17)(R), Sm_3Fe_(29), and SmFe_(12)(t) based on lattice inversion interatomic potentials. With above results, we get the vector transformation matrix in reciprocal space in comparison with the traditional transformation matrix in crystallography and analyze the reason for their similarity and difference. Finally, we discuss the stable effect of the third elements Cr, Ti to Sm_3Fe_(29). The third elements also change the lattice parameters and the X-rays diffraction pattern. The tradition matrix without considering interatomic potentials cannot reflect these differences.

关 键 词：金属间化合物 CaCu5型衍生稀土金属化合物 结构变换关系 原子相互作用势 稀土 

分 类 号：O614.33[理学—无机化学]