Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 30: Spin-Dynamics / Spin-Torque III

MA 30.9: Vortrag

Donnerstag, 26. März 2009, 12:15–12:30, HSZ 04

Spin-wave excitation in Permalloy by oscillating pinned domain walls — •Sebastian Hermsdörfer, Helmut Schultheiß, Christopher Rausch, Sebastian Schäfer, Philipp Pirro, Britta Leven, and Burkard Hillebrands — Fachbereich Physik und Forschungszentrum OPTIMAS, TU Kaiserslautern, 67663 Kaisers-lautern, Germany

In this presentation a new mechanism for the spin-wave excitation will be presented. The excitation of spin waves by oscillating pinned domain walls is an alternative approach to the well-known excitation via an antenna or, as another example, via vortex-anti-vortex-annihilation. The investigations have been carried out using micromagnetic simulations. The basic idea of the mechanism is to deflect a pinned domain wall out of its equilibrium position within the limits of the domain wall pinning. The following relaxation caused by the pinning potential which is driving the wall back towards the equilibrium position occurs as a damped oscillation with characteristic eigenfrequency. In case that the domain wall is excited by an external field with this eigenfrequency, a "steady-state" oscillation forms out with the eigenfrequency and an amplitude determined by the energy balance between the dissipation processes due to damping and the external triggering by the applied field. The energy pumped into the system by the external field leads not only to the compensation of the damping but also to the radiation of spin waves.

Financial support by the DFG within the SPP1133 is gratefully acknowledged.