Computer simulations of iron platinum nanoparticles

Self-assembled FePt nanoparticle arrays are candidate structures for ultrahigh density magnetic storage media. Some of the factors limiting their application to this technology are particle-to-particle compositional variation and particle sintering during annealing. The compositional variation affects the A1 to L10 transformation as well as the magnetic properties of the nanoparticles. Sintering destroys the ability of the particles to self assemble as well as producing large grains thereby destroying the small sizes of the nanoparticles. In the present study, an analysis of the formation mechanism of these nanoparticles is provided using Free Energy Perturbation simulations and experiments. The relationship between the size of the particle and an equilibrium composition predicted by thermodynamics is studied using Free Energy Perturbation. Sintering and its effects on the order-disorder within a pair of particles are studied using molecular dynamics simulations.