Capping-layer-induced magnetic coupling in a two-dimensional nanostructured system

The magnetic polarization of a Pt capping layer leads to an increase of the interisland magnetic coupling in a two-dimensional array of Fe islands. For small superparamagnetic islands, Pt deposition leads to a superparamagnetic–ferromagnetic transition. For larger ferromagnetic but weakly coupled islands, Pt deposition produces a stronger interisland coupling. Polar Kerr spectroscopy measurements and simulations evidence the magnetic polarization of Pt in contact with Fe. The described effects and their interpretation are supported by the use of a nonpolarizable Al capping, where both the superparamagnetic-to-ferromagnetic transition and the increase of the interisland coupling are absent. © 2004 American Institute of Physics. @DOI: 10.1063/1.1689739#