The present work reports experimental and theoretical results for
electrodeposited Co/Au(111) ultrathin layers with very specific magnetic
behavior. We show that the observed two peaks in the out-of-plane
magnetization versus deposition time variation could be explained by the
remarkably high perpendicular anisotropy of the perimeter atoms of low-
dimensional islands formed during the layer-by-layer growth, as compared to
that of the surface atoms. Our results indicate that it is possible to sustain
high anisotropy in very small grains without coming across the
superparamagnetic limit, opening excellent opportunities for materials
engineering
