First-principles calculation of magnetism of icosahedral Fe clusters
Cheng Zhi-Da(程志达), Ling Tao(凌涛), and Zhu Jing(朱静)†
Beijing National Center for Electron Microscopy, Tsinghua University, Beijing 100084, China; Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
Abstract Icosahedral iron clusters are synthesized and characterized in our group by using experimental methods. But the measurements of magnetic properties still face difficulties: the sizes of the clusters and the amount of product. Therefore theoretical methods are employed to study these issues. In this paper, icosahedral iron clusters containing 13, 55, 147, 309 atoms are calculated by ab initio techniques. After the structural relaxation, the magnetism of the clusters is found to be similar to that of face centred cubic (FCC) iron with stronger ferromagnetism on surface. But the central atom of each cluster is exceptional, which has a smaller magnetic moment. We also study the electronic structural properties in the clusters for the better explanation of the magnetism. It is suggested that in small clusters, the magnetic properties still depend on the local structural arrangement.
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