Observation of film formation process on Cu single crystal and polycrystalline substrate by molecular dynamics simulation

The giant magneto resistance (GMR) effect in Co/Cu multilayers is one of th e important issues for achieving a highly sensitive magnetic head. It is co mmonly known that GMR effect depends on the nanostructure at the interface and the grain size in the polycrystalline multilayers. For the purpose of c larifying the nanostructure at the surface during the film formation proces s, we performed molecular dynamics (MD) simulations for fabrication process es. Two different simulations were given for the Cu deposition behavior for both ii) on a Cu (111) single crystal substrate and (2) on a polycrystalli ne < 111 > textured Cu substrate. The MD simulation was also applied to the polycrystalline substrate for the quench process after melting at 1357 K. After the deposition of 0.6 Cu atoms monolayer on a single crystal substrat e. [ABC] and [AB/A] structures were observed at the surface. With increasin g the thickness of the deposition layer, [ABC] and [AB/A] structures contac ted each other, and stacking faults appeared inside the third deposition la yer. Then the grain structure appeared inside tile fourth deposition layer merely over the area where the stacking faults were observed inside the thi rd deposition layer. In case of deposition on the polycrystalline substrate , grain structures were observed in the deposition layer, which is similar to the grain structures of the substrate.