Burrowing self-organized cobalt clusters
into a gold substrate

S. Padovani, F. Scheurer and J. P. Bucher

Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, CNRS
Université Louis Pasteur - 23 rue du Loess, F-67037 Strasbourg Cedex, France

(received 11 September 1998; accepted in final form 25 November 1998)

PACS. 61.46 - Clusters, nanoparticles, and nanocrystalline materials.
PACS. 78.20Ls - Magnetooptical effects.
PACS. 61.72Cc - Kinetics of defect formation and annealing.

Abstract:

The mechanism of cobalt-cluster incorporation into a Au(111) substrate is followed by variable temperature STM, Auger spectroscopy, and in situ magneto-optic Kerr (MOKE) measurements. Upon thermal activation, cobalt clusters sink into the substrate by simultaneously expelling gold atoms which, in turn, contribute by embedding the remaining cobalt clusters. Although important mass transport occurs during this operation, MOKE indicates that the clusters remain globally undisturbed, until finally, irreversible cluster fragmentation and dissolution occur above 600 K.

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