Structural and magnetic properties of Co-Pt clusters: A spin-polarized density functional study

Abstract The structural and magnetic properties of ComPtn clusters (m + n = 2–10) are investigated using the plane wave pseudopotential method within the spin-polarized density functional theory. Four different methods are adopted to initialize the structures of Co-Pt clusters before relaxation. The lowest-energy Co-Pt clusters, the majority of which are more stable than those previously reported, are identified. Co atoms are generally located in the interior of the clusters while Pt atoms tend to be distributed near the surface. Furthermore, CoPt2, Co2Pt2, Co4Pt4, and Co6Pt4 are found to be most energetically favorable compositions. The total magnetic moment of Co-Pt clusters with ferromagnetic coupling rises almost monotonically with Co content. The magnetic moments on Co and Pt atoms in Pt-rich clusters are generally larger than those in Co-rich clusters, and both the maximum magnetic moments (2.42 µB on Co atom and 0.95 µB on Pt atom) simultaneously occur in the CoPt5 cluster. Moreover, the variation of magnetic moments, due to the introduction of single Co (Pt) atom into Pt (Co) clusters, has been examined in detail. This study is helpful to further understand the structures and magnetic properties of Co-Pt clusters, and provides a theoretical basis for designing targeted nanoalloys.