Burrowing of Co Nanoparticles on Clean Cu and Ag Surfaces

Zimmermann, C.; Yeadon, M.; Nordlund, K.; Gibson, J. M.; Averback, Robert S; Herr, U.; Samwer, K.

doi:10.1103/physrevlett.83.1163

Cited by 111 publications

(66 citation statements)

References 24 publications

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“…This is also in accordance with theoretical calculations of the atomic deposition [24]. Both intermixing as well as capping up to the point of burrowing of the cluster into the surface [25] are enhanced at temperatures well above 300K. Since our samples were prepared at room temperature, only small influences of intermixing are expected, in accordance with the results presented below.…”

Section: Resultssupporting

confidence: 91%

Monodispersed metal clusters in solid matrices: A new experimental setup

Hillenkamp

Domenicantonio

Félix

2006

Review of Scientific Instruments

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We describe a new experimental setup for the production of samples of metal clusters embedded in matrices stable at ambient conditions. The cluster ions are generated in the gas phase and codeposited fragmentation-free together with the evaporated matrix. Mean cluster sizes range from a few to many thousands of atoms. For small clusters (n < 20) mass selection is possible, larger clusters are deposited in narrow size distributions. Matrix materials include metals (Cu, Ag) and oxides such as quartz. The performance of the apparatus as well as sample characterization procedures are described. We show first results on the magnetic properties of different cobalt cluster size distributions ( n = 15, 600, 2300, 6500) embedded in copper matrices, demonstrating inter-cluster as well as cluster-lattice interactions.

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Section: Resultssupporting

confidence: 91%

Monodispersed metal clusters in solid matrices: A new experimental setup

Hillenkamp

Domenicantonio

Félix

2006

Review of Scientific Instruments

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“…The Co/Cu͑100͒ system is further stabilized when the Co atoms form clusters, and when these clusters reside in deeper layer of the substrate. The most recent experiments performed by Zimmermann et al, 24 have found a burrowing of Co nanoparticles in Cu substrate. This finding is in line with our main results.…”

Section: ͑4͒mentioning

confidence: 94%

Energetics of Co adatoms on the Cu(001) surface

et al. 2000

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By using an N-body potential scheme constructed by fitting the interaction parameters to accurate firstprinciples calculations, we investigate the structural stability of Co atoms and clusters deposited on Cu͑100͒. We found that Co atoms and clusters prefer to be embedded inside the substrate, in a way compatible with the formation of a surface alloy observed experimentally. Enhanced stability is achieved when Co atoms are deposited on a preformed Co cluster embedded on the uppermost layer of the substrate. Co atoms deposited on Co islands are best stabilized when they concur to complete the islands, by promoting layer-by-layer growth.Ultrathin films of ferromagnetic metals have found considerable interest in recent years due to their technological applications in the area of magneto-optical and transport properties. [1][2][3] In particular the growth of Fe and Co films on Cu͑001͒, which takes place pseudomorphically on the fcc substrate, has been investigated extensively.4-10 The quality of the grown layers and of the interfaces has a strong influence on properties like giant magnetoresistance, 5 magnetic anisotropy, 6,7 and oscillatory interlayer exchange coupling. 8,9Kief and Egelhoff 10 have reported the observation of nonideal film growth, characterized by the formation of compact Co clusters and the segregation of substituted Cu on the surface. Recently, the interfacial intermixing of ultrathin Co films on a Cu͑001͒ was observed, 11 despite the fact that Co and Cu are immiscible in the bulk. 12 The intermixing in the upper layers might not only be favored kinetically, but also energetically. 13In this paper we resort to a newly developed n-body interatomic potential scheme to ascertain the energetics of atoms and clusters of Co on the Cu͑001͒. A strong tendency for a direct exchange mechanism into the Cu layer is found. Our results demonstrate that at the initial stage of monolayer growth small Co clusters are formed in the Cu surface. We investigate the mechanism of adatom-cluster interactions and show how heteroepitaxial thin film growth takes place.Our approach is based on accurate first-principles calculations of selected cluster-substrate properties, which have been employed in the fitting of the potential parameters. This results in a manageable and inexpensive scheme able to account for structural relaxation and including implicitly magnetic effects, crucial for a realistic determination of interatomic interactions in systems having a magnetic nature.The potentials are formulated in the second moment tightbinding approximation ͑TB-SMA͒.14,15 The attractive term ͑band energy͒ E B i contains the many-body interaction. The repulsive term E R i is described by pair interactions ͑Born-Mayer form͒. The cohesive energy E coh is the sum of the band energy and repulsive part:. ͑3͒ r i j is the distance between the atoms i and j. r 0 ␣␤ is the first neighbor distance in the crystalline structures of the pure metals for atom-like interactions and becomes an adjustable parameter in the case of the cross interac...

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“…Recently, a strong impetus has been given to studies of nanocluster/nanostructured thin layers for two main reasons. [1][2][3][4][5][6] The first stems from the demand of miniaturization of electronic devices. Specifically, one would like to grow well-organized nanometer-size islands with specific electronic properties.…”

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confidence: 99%