Co_nAl(n=1—8)合金团簇结构和磁性质研究  

Structural,electronic and magnetic properties of Co_nAl(n=1—8) clusters

作　　者：吕瑾[1] 秦健萍[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》2013年第5期104-113,共10页Acta Physica Sinica

基　　金：山西省青年科技研究基金(批准号:2012021020-1)资助的课题~~

摘　　要：采用密度泛函理论中的广义梯度近似(DFT-GGA)对ConAl(n=1—8)合金团簇进行了系统的几何、电子结构和磁性质研究.研究结果表明Al原子倾向于与Co原子形成最大的成键数,即Al原子均处在团簇原子拥有最大配位数的位置上.Al掺杂后ConAl团簇的稳定性减弱,磁性降低.磁性降低的幅度与实验上对较大CoNAlM团簇的磁性检测结果获得了很好地符合.在所有ConAl团簇的最稳定结构中,除Co4Al外,Al与近邻Co原子均呈现反铁磁性耦合.相对于纯Co团簇,非磁性Al元素的掺入以及Al掺杂后Co原子整体自旋极化的减弱是导致ConAl团簇磁性的降低主要原因.Based on DFT-GGA calculations, we systematically investigate the structures, electronic and magnetic properties of ConAl （n = 1-8） clusters. The results indicate that the aluminum prefers to maximize the number of Co-Al bonds by selecting the site which increases the coordination of cobalt atoms with Al. The doped Al makes the stability of ConAl clusters weakened and the magnetism decreased as compared with that of Com＋1 clusters. The reduction magnitude of magnetism of the doping Al accords well with recent Stem-Gerlach experimental result for larger CoNAluclusters. In all of theConAl alloy clusters, the A1 atom is found to be aligned antiferromagnetically with its neighbor Co atoms except for Co4Al. As compared with the magnetism of pure Co cluster, the magnetism of ConAl cluster is reduced, which is attributed mainly to nor-magnetism Al element embeding and the weakening of spin polarization of the Co atoms.

关 键 词：ConAl合金团簇 几何结构 磁性 自旋极化 

分 类 号：O562[理学—原子与分子物理]