Wang Yanbiao, Chen Qian, Wang Jinlan
Department of Physics, Southeast University, Nanjing, 211189, P. R. China.
J Nanosci Nanotechnol. 2012 Aug;12(8):6488-93. doi: 10.1166/jnn.2012.5442.
We systematically investigate the structural and magnetic properties of late transition metal oxide clusters, TMnOm (TM = Fe, Co, Ni; n = 1, 2; m = 1-6) by using ab initio density functional theory approach. FenOm clusters prefer to adopt three dimensional configurations, while ConOm and NinOm clusters are apt to form planar structures. The O atoms are all atomic bonding to Fe atoms in the FenOm clusters, and are partly molecularly adsorbed to Co(Ni) in ConOm(NinOm) clusters, such as Co2O(5-6) (NiO3, and Ni2O(4-6)). The average binding energies per atom of TMnOm show a monotonous increase trend with the increase of O atoms for both n = 1 and 2 for TM = Fe, Co and Ni, and reach the peak at m = 4 for TM2Om and decrease a little bit afterwards. The odd-even magnetic oscillation is major trait with the peaks at odd and bottoms at even sizes for Fe2Om and Ni2Om (m = 2-6), respectively and large magnetic moments are found in Co2O3 and Co2O6.
我们采用从头算密度泛函理论方法，系统地研究了晚期过渡金属氧化物团簇TMnOm（TM = Fe、Co、Ni；n = 1、2；m = 1 - 6）的结构和磁性。FenOm团簇倾向于采用三维构型，而ConOm和NinOm团簇易于形成平面结构。在FenOm团簇中，O原子均以原子键与Fe原子结合，而在ConOm（NinOm）团簇中，O原子部分以分子形式吸附于Co（Ni）上，如Co2O(5 - 6)（NiO3以及Ni2O(4 - 6)）。对于TM = Fe、Co和Ni，当n = 1和2时，TMnOm每个原子的平均结合能均随着O原子数的增加呈现单调上升趋势，对于TM2Om，在m = 4时达到峰值，之后略有下降。奇偶磁振荡是主要特征，对于Fe2Om和Ni2Om（m = 2 - 6），分别在奇数尺寸时出现峰值，偶数尺寸时出现谷底，并且在Co2O3和Co2O6中发现了较大的磁矩。
