物理学报
物理學報
물이학보
2013年
5期
104-113
,共10页
ConAl合金团簇%几何结构%磁性%自旋极化
ConAl閤金糰簇%幾何結構%磁性%自鏇極化
ConAl합금단족%궤하결구%자성%자선겁화
ConAl alloy clusters%geometrical structure%magnetism%spin polarization
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.
採用密度汎函理論中的廣義梯度近似(DFT-GGA)對ConAl (n=1—8)閤金糰簇進行瞭繫統的幾何、電子結構和磁性質研究.研究結果錶明Al原子傾嚮于與Co原子形成最大的成鍵數,即Al原子均處在糰簇原子擁有最大配位數的位置上. Al摻雜後ConAl糰簇的穩定性減弱,磁性降低.磁性降低的幅度與實驗上對較大CoNAlM糰簇的磁性檢測結果穫得瞭很好地符閤.在所有ConAl糰簇的最穩定結構中,除Co4Al外, Al與近鄰Co原子均呈現反鐵磁性耦閤.相對于純Co糰簇,非磁性Al元素的摻入以及Al摻雜後Co原子整體自鏇極化的減弱是導緻ConAl糰簇磁性的降低主要原因.
채용밀도범함이론중적엄의제도근사(DFT-GGA)대ConAl (n=1—8)합금단족진행료계통적궤하、전자결구화자성질연구.연구결과표명Al원자경향우여Co원자형성최대적성건수,즉Al원자균처재단족원자옹유최대배위수적위치상. Al참잡후ConAl단족적은정성감약,자성강저.자성강저적폭도여실험상대교대CoNAlM단족적자성검측결과획득료흔호지부합.재소유ConAl단족적최은정결구중,제Co4Al외, Al여근린Co원자균정현반철자성우합.상대우순Co단족,비자성Al원소적참입이급Al참잡후Co원자정체자선겁화적감약시도치ConAl단족자성적강저주요원인.
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 Con+1 clusters. The reduction magnitude of magnetism of the doping Al accords well with recent Stern-Gerlach experimental result for larger CoNAlMclusters. In all of the ConAl alloy clusters, the Al 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.