Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 13: Topical session (Symposium EPS and MM, joint session with MA): Magnetism in Materials Science: Thermodynamics, Kinetics and Defects (joint session MM/MA)
MM 13.6: Vortrag
Montag, 12. März 2018, 18:00–18:15, TC 010
Interplay between magnetic and energetic properties in FeMn alloys from first principles — •Anton Schneider1, Chu Chun Fu1, Cyrille Barreteau2, and Frédéric Soisson1 — 1CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette, France — 2CEA, DRF, Service de Physique de l'Etat Condensé, F-91191 Gif-sur-Yvette, France
Iron-based alloys play a central role in several technological applications. In these alloys, the magnetism has an important impact on thermodynamic and kinetic behaviors, and on the properties of point defects. Especially, iron-based alloys may exhibit complex magnetic structures if the magnetic ordering tendency of the alloying element in its pure phase differs from that of iron.
Iron-Manganese bcc alloys are studied using Density Functional Theory (DFT) in order to elucidate the correlation between the magnetic structures, and the energetics of Mn atoms and clusters in the presence of vacancies and interstitial impurities. The FeMn alloys exhibit well distinct magnetic interactions between the Fe atoms and the Mn solutes depending on local chemical environments, which are rationalized in terms of electronic structures. Both low-energy magnetic collinear and non-collinear states are investigated.
The DFT results are then used to parameterize new Heisenberg-like models, in the presence of vacancies, aiming at investigating the finite-temperature magnetic effects employing Monte Carlo simulations. A particular attention is given to the role of magnetic short-range order on the vacancy formation energy, as a function of temperature.