Role of interface in forming non-equilibrium hcp phase by ion mixing in an immiscible Au-Co system

In an equilibrium immiscible Au-Co system characterized by a positive heat of formation of +11 kJ mol-1, a non-equilibrium Au-Co phase of hcp structure was formed by 200 keV xenon ion mixing at 77 K in the Au50Co50 multilayered films. Based on the free energy calculation, the excess interfacial free energy stored in the Au-Co multilayered films could provide adequate thermodynamic driving force for alloying between Au and Co and forming the non-equilibrium Au-Co hcp phase. Besides, the average magnetic moment per Co atom in the newly formed hcp structure was reduced by 22% of its equilibrium value, within a measuring error of 8%