SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Poster Session IV: Poster to Mini-Symposium: Frontiers of electronic-structure theory I
O 53.2: Poster
Dienstag, 2. März 2021, 13:30–15:30, P
Ab initio study of Heat Capacities and Energy Dispersions in Antiferromagnetic L10-type MnPt — •Kisung Kang, David G. Cahill, and André Schleife — Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
While antiferromagnetic L10-type MnPt has been utilized as a pinning layer to apply exchange bias to a nearby ferromagnetic layer, the detailed physics of magnetism in MnPt is still under the veil. We investigate ground and excited states of antiferromagnetic L10-type MnPt to understand their thermal and magnetic properties through the first-principles density functional theory. Ground-state calculations provide exchange coupling parameters, magnetocrystalline anisotropy, and metallic electronic band structure. Phonon and magnon dispersion curves are obtained from the finite difference method and linear spin-wave theory. At the Γ point a gap is expected in the magnon dispersion. Based on the energy dispersion results, we computed ab initio heat capacity for each elementary particle and the total heat capacity. The temperature dependence of the heat capacity at low temperatures originates mostly from phonons. There is almost no contribution from magnons because of the magnon gap and the low density of states in the low energy range. We use a Monte Carlo method based on the stochastic Landau-Lifshitz-Gilbert equation to compute the magnetic heat capacity in the high-temperature regime. Its peak provides the estimation of the Néel temperature, which shows good agreement with the measured value. *Illinois MRSEC NSF DMR-1720633