Formation of embedded Co nanoparticles by reaction in Al/Co multilayers and impact on phase sequence

Abstract

The formation of embedded Co nanoparticles by reaction in Al/Co multilayers and impact on phase sequence was studied. Thermodynamic considerations such as modification of free energy by curvature and stress were used to explain that the change in the phase sequence was a result of the nanostructuration of the Co layer. It was shown that the solid state reaction in multilayers lead to the formation of embedded nanoparticles. The analysis of solid-state reaction in Al/Co multilayers shows that, after the first reaction step which was the formation of Al 9Co 2, the remaining Co 'layer' can either be continuous or formed of Co nanoparticles.