Z.Zabihi, H.Araghi
Department of Physics, Amirkabir University of Technology,Tehran, Iran
E-mail: zabiholah-zabihi@aut.ac.ir
araghi@aut.ac.ir
Cluster beam can be used as a tool for produce thin films with nanostructured morphology and properties. Different method exist for cluster deposition on solid substrate such as ionized cluster beam (ICB) deposition, energetic cluster impact (ECI) and low energy cluster beam (LECB) deposition [1]. Clusters can be generated in gas aggregation, supersonic jet and surface erosion
(sputtering) sources. Ionized cluster are usually generated by electron impact after cluster formation.
One useful tool to predicting optimal deposition condition for desirable film structure is molecular dynamics (MD) simulation [2]. In this paper, we perform MD simulation of ferromagnetic (Ni, Fe and
Co) nanocluster deposition on a Cu(001) surface using tight binding potential. The ferromagnetic/ non-ferromagnetic system has applications for high density memory devices, magnetic sensors and spin electron [3].
Initially, we studied energy transformation, diffusion and penetration mechanisms in single nanocluster impact on substrate. Figure 1 shows the evaluation of kinetic energy of Ni, Fe and Co nanocluster as a function of time. The slope of energy transformation for Fe nanocluster was slower than Co and Ni cluster. Since energy per atom for Fe nanocluster was less than Co and Ni, when same total cluster energy. Because number of cluster atoms for Fe nanocluster was more than Co and Ni nanocluster, when same cluster raduis. Also, we showed depth penetration and diffiusion area of Fe nanocluster was more than Co and Ni nanocluster.
Figure 2 shows the Cu(001) surface deposited by Co nanocluster with different deposition rate after 15ps. R is surface roughness parameter that decrease with deposition rate increasing. This indicates surface is flatter in higher deposition rate. Also, we showed Cu(001) surface deposited by
Fe nanocluster was flatter than Cu(001) surface deposited by Co and Ni nanocluster.

References
[1] V.N. Popok, E.E.B. Campbell, “ Beam of Atomic Clusters: Effects on Impact with Solids ”,
Rev. Adv. Mater. Sci, 11 (2006) 19.
[2] Z.H. Hong, T.H. Fang, S.J. Lin, S.F. Hwang, “ Atomistic Simulations of Morphologhy and
Spreading Behavior of Cluster Beam Deposition ”, Comput. Mater. Sci, 49 (2010) 850.
[3] B.H. Kim, Y.C. Chung,
“
Atomic Level Investigation for Surface Characteristics in Co-Cu
Multilayer System: Molecular Dynamics Simulation ”, IEEE Trans. Magn, 44 (2008) 2903
Figure 1: Kinetic energy of the cluster as a function of time.
Figure 2: The sanapshots of the Cu(001) surface deposited by Co nanocluster after 15ps with deposition rate: a)1 cluster/ps b) 2 cluster/ ps c) 3 cluster/ps.