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 an organic matrix, while nanocolumns are only obtained under very specific conditions. Experiments [Greve et al. Appl. Phys. Lett. 88, 123103 (2006)] 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 a 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 on the formation of Fe-Ni-Co nanocolumns in a Teflon AF matrix via co-evaporation down to a deposition temperature of -70 degrees C and also report the magnetic properties of the nanocolumns. The simulations provide a detailed understanding of the transition from spherical cluster growth to formation of elongated structures and are in good agreement with the experiments. (C) 2013 AIP Publishing LLC.