Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 41: Micromagnetism / Computational Magnetics
MA 41.2: Talk
Wednesday, March 22, 2017, 15:15–15:30, HSZ 101
Interdependence of the spin and lattice dynamics of CrN in the high temperature paramagnetic phase — •Irina Stockem1,2 and Björn Alling1,2 — 1Department of Physics, Chemistry, and Biology (IFM), Linköping University, Sweden — 2Max-Planck-Institut für Eisenforschung Düsseldorf, Germany
The combined magnetic and structural phase transition at the Néel temperature spurred interest to use CrN as a model system in the development of first-principles based theoretical modeling schemes of paramagnetism. While antiferromagnetic CrN exhibits an orthorhombic crystal structure at low temperatures, the crystallographic ordering becomes cubic rock salt in the paramagnetic range. It is known that the local magnetic moments of the Cr atoms do not vanish even at high temperature and their varying orientation of the magnetic moments as well as the lattice vibrations should be considered when the paramagnetic phase is simulated.
Up to now, this has been done using a combination of ab-initio molecular dynamics with rapidly changing disordered local moments electronic structure method for paramagnetism (DLM-MD). We go beyond the adiabatic approximation for the time dynamics of the magnetic degree of freedom and combine atomistic spin dynamics with ab initio molecular dynamics. A separate spin dynamics and molecular dynamics study of CrN uncovers similar time scales of the vibrations and the spin decoherence time, clearly motivating our development of the combined ASD-AIMD approach to study interdependency between spin and lattice degrees of freedom.