Formation of ultrathin magnetic cobalt films on the Si(111)7 × 7 surface

Abstract

The phase composition, electronic structure, and magnetic properties of ultrathin cobalt films (no thicker than 20 A) applied on a Si(111)7 × 7 surface at room temperature are studied by high-resolution photoelectron spectroscopy using synchrotron radiation and magnetic linear dichroism. It is shown that, as the cobalt thickness increases, first interface cobalt silicide and then an island (discontinuous) film of silicon-in-cobalt solid solution form on the silicon surface. A metal cobalt film starts growing after the deposition of a ∼7-A-thick Co layer. It is found that the ferromagnetic ordering of the system, which is characterized by surface magnetization, sets in after the deposition of a ∼6-A-Co layer at the stage of Co-Si solid solution formation.