Effect of cohesive energy on atomic transport in ion beam mixed Co/Pt bilayer film

The mechanism of phase formation in Pt/Co bilayers during ion beam mixing

“…As per the model proposed by Jung et al [12] the atomic transport at the interface between two metallic thin films depends on their atomic radius, deposited energy by nuclear stopping in the metallic targets and their cohesive energy. For the case of Pt/Co bilayer, there is enhanced motion of Co atoms into Pt layer at 300°C because of difference in cohesive energy between Co (4.39 eV) and Pt (5.84 eV) and it is experimentally verified [13,14]. The cohesive energy effect is clearly visible in our results also, as we observe a major fraction of Co atoms diffuse into top Pt layer.…”

“…To overcome the shortcomings of atomic size effect proposed by Ding et al [9] and radiation damage density effect proposed by Tao et al [10] a new model was developed by Jung et al [12] that predicted the dominant moving species during ion beam mixing. Subsequent ion irradiation experiments performed on bilayer film [13,14] successfully verified the model proposed by Jung et al [12].…”

“…RBS observations suggest that the enhanced Co atomic motion towards top Pt layer synthesizes CoPt, Co 3 Pt phases without forming silicide phases. The enhanced Co atomic motion towards top platinum layer at 300°C was predicted by the model put forward by Jung et al [12] and has been experimentally verified for Co/Pt bilayer film [13]. Two distinct regimes were identified in the model, the atomic transport in the collision cascade regime and the thermal spike regime, were suggested to be in the athermal regime and that in the radiation enhanced diffusion (RED) regime to be in the temperature dependent regime.…”

“…Two distinct regimes were identified in the model, the atomic transport in the collision cascade regime and the thermal spike regime, were suggested to be in the athermal regime and that in the radiation enhanced diffusion (RED) regime to be in the temperature dependent regime. As per the model, at the Co/Pt interface, in the RED regime, the diffusion of Co atoms into the Pt layer is enhanced, while in the athermal regime the diffusion of Pt atoms and the Co atoms across the interface is almost equal, due to the difference in their cohesive energies [13,14]. However, the model is suitable only for metallic systems and not suitable for semiconductors [13].…”

“…As per the model, at the Co/Pt interface, in the RED regime, the diffusion of Co atoms into the Pt layer is enhanced, while in the athermal regime the diffusion of Pt atoms and the Co atoms across the interface is almost equal, due to the difference in their cohesive energies [13,14]. However, the model is suitable only for metallic systems and not suitable for semiconductors [13].…”