Influence of overlayer thickness on the density of Lomer dislocations in nanoscale Ni–Cu bilayer thin films

Abstract

We report on the evolution of the spacing and the character of misfit dislocations with increasing Ni overlayer thickness at an (001) Ni–Cu interface. At low Ni overlayer thicknesses (3 and 5nm), most of the interface dislocations are 60°1∕2⟨110⟩ glide dislocations, while Lomer edge dislocations constitute only about 5% of the total interface dislocation content. At a 13nm Ni overlayer thickness, the fraction of Lomer dislocations increases to approximately 40% of the total content. This dramatic increase in the fraction of Lomer dislocations is likely related to a “rebound mechanism” which initiates at some critical thickness between 5 and 13nm.