Thermodynamic and ballistic aspects of ion mixing

Ballistic and thermal spike contributions to ion mixing are discussed using the results of recent marker experiments which determine the dominant moving species in ion mixing of several metallic bilayer systems. A greater flux of atoms from the high cohesive energy side to the low cohesive energy side is the result of the thermal spike contribution to ion mixing. A greater flux from the top layer to the bottom layer in ion mixing of bilayers consisting of elements of similar and high cohesive energy values is the result of the ballistic contribution to ion mixing. The relative importance of ballistic and thermal spike contributions is influenced by the magnitude of cohesive energy. A model based on a fractal geometry approach to spike formation is used to understand the competition between ballistic and thermal spike contributions to ion mixing.