Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Methods in Computational Materials Modelling I: Ab initio thermodynamics

MM 41.6: Vortrag

Mittwoch, 9. März 2016, 17:15–17:30, H52

The effects of lattice vibrations on electronic and magnetic properties of paramagnetic Fe: A disordered local moments molecular dynamics study — •Björn Alling — Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf — Linköping University, Sweden

High temperature lattice vibrations in the paramagnetic states of Fe is studied employing the disordered local moments molecular dynamics (DLM-MD) method. In particular its impact on the magnetic and electronic structure is investigated. It is found that lattice vibrations strongly affect the local magnetic moment distribution which correlates with the local atomic volumes. Without explicit vibrations, the mean local magnetic moment and mean field derived magnetic entropy in paramagnetic bcc Fe are larger in comparison to paramagnetic fcc Fe which would indicate that magnetic degree of freedom contribute to stabilize the bcc phase at high temperatures. However, when explicit lattice vibrations are taken into consideration, the picture is changing at high temperature and very similar local magnetic moment distributions and mean-field magnetic entropies of bcc and fcc Fe are found close to the γ to δ transition. This qualitative change, due to vibrations, is consistently observed in the electronic density of states which are found to become equally similar with increasing temperature. Our findings illustrate the need for an explicit consideration of vibrational disorder and its impact on electronic and magnetic properties to understand paramagnetic Fe.