Magnetism of small Fe clusters on Au(111) studied by x-ray magnetic circular dichroism - art. no. 104429

Epitaxial growth of Fe. on a reconstructed Au(111) surface leads to the for mation of self-organized fcc Fe dots and stripes with increasing coverage. Using the sensitivity of x-ray magnetic circular dichroism (XMCD) and sum r ule analysis, the chances in the magnetic properties in the low thickness r ange from similar to0.1% of a monolayer (ML) to 4 ML, covering the unidimen sional (1D) coalescence around similar to0.3 ML and the two- dimensional pe rcolation limit around similar to1 ML have been determined. The evolution o f the spin moment (M-spin) as, a function of the thickness is correlated to the morphological transition. In particular, m(spin) increases sharply at the ID coalescence, what is attributed to a transition from a low-spin to a high-spin magnetic phase. We also observe a flipping of the easy axis of m agnetization at the ID coalescence from in-plane to out-of-plane. This unus ual behavior is ascribed to the strong in-plane relaxation of the Fe films due to the particular pseudomorphic growth of Fe on the reconstructed Au(11 1) surface.