Patterned nanostructure in AgCo/Pt/MgO(001) thin film

TL;DR

This study uses simulation techniques to investigate how dislocation networks influence the formation of patterned nanostructures in AgCo/Pt/MgO(001) thin films, revealing conditions for controlling their distribution.

Contribution

It introduces a combined molecular dynamics and phase-field simulation approach to analyze pattern transfer from dislocation networks to nanostructures in thin films.

Findings

Patterned Co islands are attracted by dislocation networks.

Pattern formation is limited to near the interface unless diffusion is minimized.

Controlling film growth can promote uniform patterned structures throughout the film.

Abstract

The formation of patterned nanostructure in AgCo/Pt/MgO(001) thin film is simulated by a technique of combining molecular dynamics and phase-field theory. The dislocation (strain) network existing in Pt/MgO is used as a template whose pattern is transferred to AgCo phase in spinodal decomposition, resulting in regular arrays of Co islands that are attracted by the dislocations. The influence of various factors, such as component concentration and film thickness, is studied. It is found that the spinodal decomposition of AgCo in this system is mainly characterized by a competition between a surface-directed layer structure and the strain-induced patterned structure, where the patterned Ag-Co structure only dominates in a small range near the interface (less than 10 atomic layers). However, if the interlayer diffusion can be minimized by controlling film growth conditions, it is shown that the patterned structure can be formed throughout the entire film.