Revisit of Magnetism of Fe overlayers on Cu(001)

Fe films on Cu(001) have drawn a great attention due to the complicated structural and magnetic properties. It is known from the previous investigations that depending on the Fe thickness, Fe/Cu system has three distinguishable regions in terms of the structural and magnetic properties. Especially the spin structure in region II, where the film thickness ranges from 5 ML to 11 ML, has been controversial for the last two decades. We have studied the spin structure of Fe films on Cu(001) in region II via x-ray magnetic circular dichroism (XMCD) and surface magneto-optic Kerr effect (SMOKE) measurements. Wedge-shaped Fe films, which ranged from 6 ML to 10 ML, have been grown on Cu(001) at room temperature by an e-beam evaporator. Our results suggest a new model, which is totally different from the previous models, based on the incommensurate spin density wave.