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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 Swiebodzinski2,3, Massoud Najafi4, Gunnar Selke4, André Drews1, Guido Meier1, and Markus Bolte1,4 — 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)