Magnetic and electrical properties of Co/Si multilayer thin films

Abstract

This paper reports on the effects of interlayer mixing and a solid-state alloying reaction on the properties of a Co/Si multilayer system. The compositionally modified structure changes from a CoSi alloy to Co/CoSi to CoSi/Si layered systems as the nominal thickness of Si is increased over that of Co. The temperature-dependent magnetic properties of the multilayers are complex, with ferromagnetic and also thermally unstable superparamagnetic properties characterized by a blocking temperature behavior typical of small, low anisotropy particles. The electrical resistivity charts a transition from metallic to nonmetallic character as a function of increasing Si content. Resistivity minima and large magnetic saturation fields at low temperatures suggest the presence of Kondo-like behavior typical of dilute alloys.