Structure, composition and magnetic properties of size-selected FeCo alloy clusters on surfaces

The magnetic properties of 3d-metal clusters significantly differ from bulk behavior. This phenomenon is caused by a narrowing of electronic states and the high ratio of surface to volume atoms giving rise to enhanced magnetic orbital moments. FeCo alloys as soft magnetic materials are known to exhibit very high magnetic moments. The spin and orbital moments of iron and cobalt in size-selected FeCo alloy clusters on non-magnetic as well as magnetized nickel substrates have been investigated by X-ray magnetic circular dichroism with elemental specification. Structural properties were determined by scanning probe measurements. The preformed clusters maintain their original three-dimensional shape with a tendency to a slightly oblate occurrence, which can be explained by particle–support interaction, and do not change to a more or less two-dimensional formation after deposition.