【摘要】 用自旋极化的MS-Xα方法研究了原子簇Sm5Co28Si6的电子态密度、自旋能级劈裂及原子磁矩。结果显示,由于Sm-Co间的轨道杂化效应,使Sm原子的5d0空轨道上占据了少量5d电子。Co(3d)-Sm(5d)电子间的直接交换作用,构成Sm-Co间的主要耦合方式,这是化合物SmCo5.85Si0.90中形成铁磁性长程序的一个重要因素。Si的掺杂使2e晶位的负交换耦合作用明显减弱,Ferm i面处电子间键合作用增强,化合物的系统自由能降低,从而有利于形成稳定的铁磁性结构。考虑到深层4 f电子的局域性以及轨道杂化效应所产生的少量5d电子,可以得到Sm的原子磁矩为1.24μB,与顺磁盐中Sm3+的磁矩实验值(1.32~1.63μB)基本符合。更多还原

【Abstract】 Electronic structures of Sm₅Co₂₈Si₆ cluster were studied by using spin-polarized MS-Xα method.The results show that a few of electrons are transferred to Sm（5d⁰） orbit because of orbital hybridization between Sm and Co atoms.The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co,and that results in the long-range ferromagnetic order in SmCo_5.85Si_0.90.The calculated results for the cluster reveal that SmCo_5.85Si_0.90 is stable phase.Since the spin-up DOS peak of d electrons at E_F rises and the bonding of electrons at E_F strengthens with increasing Si concentration,the free energy of alloys decreases and the stable ferromagnetic order forms in SmCo_5.85Si_0.90.Considering the localization of 4f electrons and a few of 5d electrons,the magnetic moment of Sm will be 1.24μB which is in agreement with the experiments of Sm³⁺ ion-moment in metals（1.32¹.63μB）.更多还原