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MM: Fachverband Metall- und Materialphysik

MM 7: Transport - Atoms and Ions II

MM 7.4: Vortrag

Montag, 16. März 2020, 12:30–12:45, IFW A

Atomistic spin-dynamics simulation of self-diffusion in bcc Fe — •Sergei Starikov, Matous Mrovec, and Ralf Drautz — ICAMS, Ruhr-University, Bochum, Germany

We investigate vacancy diffusion and atomic self-diffusion in bcc iron using a combined lattice-dynamics and spin-dynamics simulation. The spin subsystem is simulated by a classical Heisenberg model that takes into account the exchange interaction between pairs of magnetic spins. The interactions between atoms were described by a new interatomic potential developed in this work using the force-matching method. This method enables to reproduce with high fidelity energies, forces and stresses computed at the ab initio level for a fine-tuned set of reference structures. An extended validation of elastic, thermophysical and defect properties has demonstrated a wide range of applicability of the potential. The diffusion simulations reveal a strong dependence of vacancy formation energy on temperature that leads to a non-Arrhenius behaviour of the self-diffusion coefficient. The simulation results are compared with available experimental data.