Magnetism of nanostructures studied by x-ray magnetic circular dichroism: Fe on Cu(111)

Epitaxial growth of Fe on a stepped Cu(111) surface leads to the formation of fee Fe stripes along the step edges for coverages lower than 1.5 monolay er (ML). Using the sensitivity of the x-ray magnetic circular dichroism and sum-rule analysis, the changes in the magnetic properties in the low thick ness range from similar to 5% of a monolayer to 4 ML, covering the one-dime nsional (1D) coalescence (similar to 0.8 ML) and the 2D percolation limit ( similar to 1.5 ML), have been determined. The determination of the spin mom ent (m(spin)) indicates significant features which can be correlated to the morphological transition. In particular, the m(spin) decreases at the 1D c oalescence limit, but increases as the film reaches the 2D percolation limi t and starts to transform into the bcc phase. This behavior is tentatively ascribed to the decrease in the Fe atomic volume, as it is well known that such changes can dramatically modify the magnetic properties of gamma-Fe.