Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 14: Micromagetic Simulation and Electron Theory of Magnetism

MA 14.5: Vortrag

Dienstag, 12. März 2013, 10:30–10:45, H23

Low temperature magnetic phase of bulk MnSi: An ab initio study — •Giovanna Lani, Gustav Bihlmayer, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany

The magnetic phase diagram of bulk MnSi has been the object of several experimental and theoretical studies over the years, recently receiving renewed interest, due to the debated nature of its magnetic order around the Curie temperature upon the application of a small magnetic field. On the other hand, it is well established from neutron scattering experiments, that at low temperature MnSi exhibits helical spin spiral order along the ⟨ 111 ⟩ direction. Employing density functional theory calculations based on the full-potential linearized augmented plane wave method as implemented in the FLEUR code [1], we carry out a comprehensive study of the exchange interactions in this system and present here our preliminary results. Working in the adiabatic approximation, we evaluate the Heisenberg exchange parameters (J_ij) and compare their behavior with the one expected by the RKKY interaction for ferromagnets. The J_ij coefficients are then employed to calculate the energy of spin spirals with different wave vectors. Finally we estimate the Curie temperature via mean field approximation and Monte Carlo calculations and compare it with previous calculations and available measurements.

[1] www.flapw.de