Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 9: Micromagnetism/Computational Magnetics

MA 9.2: Vortrag

Montag, 25. Februar 2008, 17:00–17:15, H 1012

Hybrid FEM-BEM method for Oersted field calculation — •Riccardo Hertel — Forschungszentrum Jülich, Institut für Festkörperforschung IFF-9, D-52425 Jülich

Various exciting aspects of the current-induced magnetization dynamics in nanostructures due to spin-transfer torque effects have attracted overwhelming interest recently, particularly in the past five years. The interest in this new kind of spin dynamics is in fact so great, that the classical interaction between the magnetization and electric currents due to Maxwell has almost been overlooked. In the case of nanomagnets excited by a spin-polarized current in a pillar geometry, however, the magnetic field created by the current (i.e., the Oersted field) often provides a non-negligible contribution to the magnetization dynamics. Hence, micromagnetic simulations on current-driven dynamics require methods for accurate calculation of the Oersted field. In principle, the whole current-carrying structure (including, e.g., the contacting leads and the magnetic pillar) needs to be considered for reliable Oersted field calculation, i.e., a region which is much larger than the nanomagnet itself. In this talk I will present a hybrid finite-element / boundary method for the calculation of current density distributions and the resulting Oersted field in general geometries. This method can be easily implemented in finite-element micromagnetic simulation techniques because the involved matrix elements are the same as those used for the magnetostatic (dipolar) interaction.