Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 38: Theory of strongly correlated systems

MA 38.13: Vortrag

Donnerstag, 15. März 2018, 13:00–13:15, H 0110

Calculated Curie temperatures of metallic ferromagnets — •Roman Kováčik, Phivos Mavropoulos, Konstantin Tillmanns, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

We analyze the predictive power of the local density approximation, generalized gradient approximation, and disordered local moment method in connection with the classical Heisenberg model to determine the critical temperature of the magnetic phase transition for a large set (about 100) of bulk materials from the Heusler family alloys. To obtain the electronic structure we employ the ab initio Korringa-Kohn-Rostoker Green function method [1] where the exchange parameters are calculated by the method of infinitesimal rotations [2]. The magnetization curve as a function of temperature is simulated by the Monte Carlo method. The fourth-order cumulant is used to determine the critical temperature while its convergence is ensured with respect to the exchange parameters cut-off distance and the supercell size of the Monte Carlo simulation. Finally, we evaluate the effective magnetic moment and analyze our results in comparison with the experimental data. Support from JARA-HPC (jara0051) is gratefully acknowledged. [1] H. Ebert et al., Rep. Prog. Phys. 74, 096501 (2011), also see: www.kkr-gf.org. [2] A. I. Liechtenstein et al., J. Magn. Magn. Mater. 67, 65 (1987).