Burrowing self-organized cobalt clusters into a gold substrate

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.