Ferromagnetic alignment of iron nanostructures on the silicon surface

Abstract

The phase composition, electronic structure, and magnetic properties of nanostructures formed upon deposition of iron on the surface of the Si(556) vicinal face coated by a submonolayer silver film with a √3×√3-Ag structure have been studied using high-energy-resolution photoelectron spectroscopy and analysis of magnetic linear dichroism in photoemission of Fe 3p electrons. The effective thickness of the deposited iron layer is varied from 1 to 25 A. It has been shown that a 1- to 2-A Fe coverage leads to the formation of a metastable iron silicide thin layer with a CsCl-type structure on the surface of the sample. A further deposition of Fe (up to ≈7 A) brings about the formation of chains consisting of nonmagnetic islands of the Fe—Si solid solution on this layer, which are oriented along the steps of the substrate. A ferromagnetic alignment of the system along the surface of the sample appears only at coverages of approximately 10 A, when larger (≈100 nm) iron islands start to grow on the solid solution layer.