Formation of magnetic nanocolumns during vapor phase deposition of a metal-polymer nanocomposite: experiments and kinetic Monte Carlo simulations

Metal-polymer nanocomposites have been investigated extensively during the last years due to their interesting functional applications. They are often produced by vapor phase deposition which generally leads to the self-organized formation of spherical metallic nanoparticles in the organic matrix, while nanocolumns are only obtained under very specific conditions. Experiments\cite{Grev+06} have shown that co-evaporation of the metallic and organic components in a simple single-step process can give rise to the formation of ultrahigh-density Fe-Ni-Co nanocolumnar structures embedded in a fluoropolymer matrix. Here we present a kinetic Monte Carlo approach which is based on an new model involving the depression of the melting point on the nanoscale and a critical nanoparticle size required for solidification. In addition we present new experimental results down to a deposition temperature of \cel{-70} and also report the magnetic properties. The simulations provide a detailed understanding of the transition from spherical cluster growth to formation of elongated structures and are in quantitative agreement with the experiments.