Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 24: Spindynamics / Switching II

MA 24.6: Talk

Thursday, March 29, 2007, 11:30–11:45, H23

Dynamic Quasi-Particle Behaviour of Geometrically Confined Domain Walls — •Daniel Bedau, Mathias Kläui, and Ulrich Rüdiger — Universität Konstanz, 78467 Konstanz

Magnetic domain walls in laterally confined elements feel the potential landscape generated by notches. Depending on its type the domain wall is either symmetrically pinned inside of the notch (transverse wall) or pinned adjacent to the notch (vortex wall)[1]. This pinning allows to reliably switch magnetic domain walls between different positions, because of the long range of the attractive potential which locks the domain walls to the notch positions. The width of the potential, the depth, corresponding to the pinning strength, and the angular dependence of the pinning potential have been published [2,3,4]. Because of their small lateral extensions domain walls can act like quasi particles oscillating in a potential well, which allows us to study the potential by measuring the oscillation frequency of the domain wall. We have chosen to study magnetic rings, because the ring structure allows precise control of the domain wall spin structure via the lateral dimensions and the thickness of the film. To measure the structure of the potential, a new setup has been built to determine the influence of microwave excitations on the electrical properties of domain walls in the range from 10 MHz up to 20 GHz at low temperatures. [1] M. Kläui et al., Phys. Rev. B 68, 134426 (2003), Physica B 343, 343 (2004) [2] M. Kläui et al., Phys. Rev. Lett. 90, 97202 (2003) [3] M. Kläui et al., Appl. Phys. Lett. 87, 102509 (2005) [4] D. Bedau et al., J. Appl. Phys., (in press 2007)