Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 19: Spin Dynamics / Spin Torque I

MA 19.8: Talk

Wednesday, February 27, 2008, 15:45–16:00, EB 301

Direct observation of the Walker breakdown process during domain wall (dw) propagation in Permalloy nanowires — •Sascha Glathe and Roland Mattheis — IPHTJena e.V., A.-Einstein-Str.9, D-07745 Jena

The Walker breakdown process determines the field driven dw movement in nanowires above a critical magnetic field Hw. Until now there are only some simulations adressing this process, mainly in ideal structures. An adequate experimental verification is not offered yet.

We explored the dw propagation in 150 nm wide, 15 nm thick permalloy films, which are the sense layer of GMR stacks. The dw movement was examined due to time resolved measurements of GMR stack resistance. During the dw motion we find periods of steady dw movement and periods where the dw stops. These time domains are in the order of some ns and are repeated alternately. We attribute this behaviour of the dw to the Walker breakdown process. Thus we provided a direct experimental evidence of the Walker breakdown process.