Structural, magnetic, and electronic properties of small M-Pt (M = Fe, Co, and Ni) clusters: Insight from density-functional calculations

Abstract

Structural, magnetic, and electronic properties of M13−nPtn (M = Fe, Co, and Ni) clusters are investigated using the plane wave pseudopotential method within the spin-polarized density-functional theory. Some novel lowest-energy configurations, superior to those reported so far, are identified in this work. There exist markedly structural differences among M13−nPtn clusters with the same M/Pt ratios except for M10Pt3, M9Pt4, and M5Pt8. All these clusters display the same trend of atomic distribution, that is, M atoms are preferentially located in the interior and Pt atoms tend to occupy the sites near surface. The magic compositions with better stability are found to be Fe7Pt6, Co6Pt7, and Ni6Pt7. The magnetic moments of M atoms in M-Pt clusters are sensitive to the charge transfer and geometric structure. In comparison to the M clusters, alloying of Pt with M atoms noticeably enhances the magnetic moments of Fe and Co atoms in Fe-rich and Co-rich clusters, and those of Ni atoms in all Ni-Pt clusters. According to the electronic density of states and Bader charge analysis, it is found that with increasing Pt content in M13−nPtn clusters, the spin-up channel has a shift toward higher energy level, and the average amount of charge transferred from M to Pt atoms gradually increases.