Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.30: Poster

Friday, March 26, 2010, 11:00–14:00, Poster B1

Cell-size independent micromagnetic simulations including thermal effects — •Claas Abert¹, Benjamin Krüger², Jacek Swiebodzinski^2,3, Massoud Najafi⁴, Gunnar Selke⁴, André Drews¹, Guido Meier¹, and Markus Bolte^1,4 — ¹Institut für Angewandte Physik, Universität Hamburg, Germany — ²Institut für Theoretische Physik, Universität Hamburg, Germany — ³Theoretische Physik, Universität Duisburg-Essen, Germany — ⁴Arbeitsbereich Technische Informatik Systeme, Department Informatik, Universität Hamburg, Germany

Micromagnetic simulations are a well established and powerful tool for zero temperature problems. Since experiments show that temperature strongly influences the magnetization dynamics, it is important to include thermal effects into the micromagnetic approach. This can be done by introducing an effective fluctuating field. The variance of this field is determined by solving the micromagnetic Fokker-Planck equation and demanding a Boltzmann distribution in thermal equilibrium [1]. A remaining challenge is the dependence of the simulation results on the simulation cell-size. This dependence can be eliminated by renormalizing simulation constants. Here a renormalization of the saturation magnetization and exchange constant is investigated using a finite difference micromagnetic simulation tool with a second-order Runge-Kutta stochastical integrator. A correction factor is found that solely depends on well-known simulation constants and which reduces the error by up to an order of magnitude as compared with previous approaches. [1] J. García-Palacios et al., Phys. Rev. B 58 14937 (1998)