Origin of step-like behavior in the Co/Si system

A systematic investigation of the structure, nature of the interface and their possible connections with magnetic properties for the as-deposited Co/Si/Co trilayer system has been carried out. X-ray reflectivity, cross-sectional transmission electron microscopy and x-ray emission measurements performed on the Co/Si/Co trilayer system show that when the Si layer thickness is less than ∼ 20 A, the full Si layer is converted into a cobalt silicide layer whereas when the Si layer thickness > 20 A along with the silicide layer. the pure Si layer also remains. A comparison of magneto-optical Kerr effect and magnetoresistance measurements reveals the absence of antiferromagnetic coupling in these samples. Double-step-like magnetization, in the case of Si layer thickness > 20 A between two Co layers, is explained by magnetization reversal of two ferromagnetic layers having different coercivities, independent of each other.