Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 30: Methods in Computational Materials Modelling III: Thermodynamics

MM 30.1: Vortrag

Mittwoch, 18. März 2015, 10:15–10:30, H 0106

Magnetic materials at high temperature from first-principles: disordered magnetism, vibrations, phase stability and magnetic exchange interactions — •Björn Alling — Department of Physics, Chemistry, and Biology, Linköping University, Sweden

First-principles based approaches faces considerable challenges in modeling magnetic materials at high temperature due to the complexity of simultaneously treat the relevant magnetic, vibrational, and structural excitations. Here a first-principles framework is presented capable of calculating thermodynamic and magnetic properties of magnetic materials in their high-temperature paramagnetic state.

Calculations of temperature dependent vibrational spectra, Gibbs free energies and corresponding phase stabilities are based on the disordered local moments-molecular dynamics (DLM-MD) [2,3] The phonon spectra and pressure-temperature dependent phase transition of the hard coating material CrN is derived [5].

Furthermore, the effects of vibrations and structural disorder on the magnetic exchange interactions are derived. We use our approach to calculate the magnetic interactions of amorphous CrN illustrating the effects on magnetism in an extreme case of structural disorder. [6]

[1] B. Alling, T. Marten, and I. A. Abrikosov, Nature Materials 9, 283 (2010) [2] P. Steneteg, B. Alling, and I. A. Abrikosov, PRB 85, 144404 (2012) [3] B. Alling, L. Hultberg, L. Hultman, and I. A. Abrikosov, APL 102, 031910 (2013) [5] N. Shulumba, B. Alling, et al., PRB 89, 174108, (2014) [6] A. Lindmaa, R. Lizaraga, E. Holmström, I. A. Abrikosov, and B. Alling, PRB 88, 054414 (2013)