摘要
用快速急冷方法制备了Ho_2Fe_(17)C_x化合物,研究了它们的形成、结构与磁性。这些化合物在高温下是稳定的,随C含量的增加,晶体结构由六角Th_2Ni_(17)型转变为菱形Th_2Zn_(17)型。测量了Ho_2Fe_(17)C_x化合物在1.5K和室温下的饱和磁化强度,得到每个Fe原子磁矩近似与C含量无关。C原子的引入导致了单胞体积的膨胀和居里温度的增加,利用分子场模型得到,居里温度随x的增加而提高主要是由于间隙C原子的作用增强了Fe-Fe原子间的交换作用所致。
Formation,structure and magnetic properties of Ho2Fe17Cx compounds prepared by melt-spinning were studied. These carbides are found to be stable at high temperature. Their crystal structure changes from the hexagonal Th2Ni17-type to rhombohedral Th2Zn17-type,as x increases. Saturation magnetization of Ho2Fe17Cx compounds at 1. 5 and 300K were measured, and no dependence of Fe magnetic moment on carbon concentration was found. The introduction of carbon atoms results in the expansion of unit cell volumes and the rising of Curie temperature. According to the molecular field model,we suggest that the rising of Curie temperature with x is mainly due to the enhancement of Fe-Fe exchange interactions by introduction of interstitial carbon atoms.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1993年第12期1998-2004,共7页
Acta Physica Sinica
基金
国家自然科学基金
关键词
钬合金
稀土铁合金
结构
磁性
Crystal structure
Magnetic properties
Stability
