Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 14: Cooperative Phenomena: Spin Structures and Magnetic Phase Transitions
MA 14.4: Vortrag
Dienstag, 6. September 2022, 10:30–10:45, H47
Ab initio approach to compute magnetic Gibbs free energies and phase transitions using magnetically constrained supercells — •Eduardo Mendive Tapia1,2,3, Nicolas Essing1, Rudolf Zeller1, Stefan Blügel1, Jörg Neugebauer2, and Tilmann Hickel2 — 1Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — 2Max-Planck-Institut für Eisenforschung, 40237 Düsseldorf, Germany — 3Universitat de Barcelona, D-08028 Barcelona, Spain
We present a first-principles approach for the computation of the magnetic Gibbs free energy of materials using magnetically constrained supercell calculations [1]. Our approach, based on an adiabatic approximation for the local moment orientations [2], describes magnetic phase transitions and how electronic and magnetovolume mechanisms generate a discontinuous (first-order) character. Results obtained for bcc Fe and the triangular antiferromagnetic state of Mn3AN (A = Ga, Ni) [3] will be presented and used to explain their negative volume expansion and the first-order nature observed experimentally. The performance of two different density functional theory codes, the Vienna Ab Initio Simulation package (VASP) and the linear-scaling KKR-nano code suitable for thousands of atoms (https://jukkr.fz-juelich.de), will be shown.
[1] E. Mendive-Tapia, J. Neugebauer, T. Hickel, Phys. Rev. B 105, 064425 (2022).
[2] B. Gyorffy et al., J. Phys. F: Met. Phys. 15 1337 (1985).
[3] D. Boldrin et al., Phys. Rev. X 8 041035 (2018).