Co_mAl_n(m+n≤6)团簇的结构和磁性理论研究  

Structural, electronic and magnetic properties of Co_mAl_n(m+n≤6) clusters

作　　者：秦健萍[1] 梁瑞瑞[1] 吕瑾[1] 武海顺[1] 

机构地区：[1]山西师范大学化学与材料科学学院,临汾041004

出　　处：《物理学报》2014年第13期74-83,共10页Acta Physica Sinica

基　　金：国家自然科学青年基金(批准号:21301112);教育部博士点基金(批准号:20131404120001);山西省自然科学基金(批准号:2012021020-1)资助的课~~

摘　　要：采用密度泛函理论中的广义梯度近似(DFT-GGA)对ComAln(m+n 6)合金团簇进行了系统的几何、电子结构和磁性质研究.研究结果发现ComAln(m+n 6)团簇最稳定结构倾向于形成Co—Al成键数最多的构型,其中的Co—Al二元合金团簇的最稳定结构类似于纯钴团簇.随着Al原子数的增多,团簇的平均磁矩呈线性降低趋势.ComAl(m=2—5)团簇的总磁矩均比Com+1团簇的小4μB,与实验上对较大CoNAlM团簇的磁性检测结果获得了很好地符合.ComAln团簇磁性的降低主要归因于非磁性Al元素的掺入以及Al掺杂后Co原子的整体自旋极化减弱.Based on DFT-GGA calculations, we investigate systematically the structural, electronic and magnetic properties of ComAln（m＋n≤6） clusters. The calculated results show that the most stable structure of ComAln（m＋n≤6） clusters prefers to form the maximized number of Co—Al bonds, and is more similar to the most stable structure of pure cobalt clusters. With increasing Al atom numbers, the average magnetism of the clusters is reduced linearly. The magnetism of the ComAl （m = 2—5） clusters is 4 μB smaller than that of Com＋1 clusters, this agrees well with the recent Stern-Gerlach’s experimental result of magnetism detection for a larger size of CoN AlM cluster. Reduction of the magnetism of ComAln clusters is mainly attributed to the non-magnetic Al element embeded and the weakening of spin polarization of the Co atoms.

关 键 词：ComAln合金团簇 几何结构 磁性 自旋极化 

分 类 号：O469[理学—凝聚态物理]