Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Poster II
MA 33.60: Poster
Freitag, 26. März 2010, 11:00–14:00, Poster B1
Imaging of field induced domain wall excitation in permalloy nanowires — Jan Rhensius1,2, •Daniel Rüffer2, Lutz Heyne2, Stephen Krzyk2, Laura Jane Heyderman1, Frithjof Nolting1, and Mathias Kläui2 — 1Paul Scherrer Institut, 5232 Villigen PSI, Switzerland — 2Fachbereich Physik, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany
We present time resolved imaging of the spin structure of a magnetic head-to-head DW induced by an applied magnetic field pulse, using a pump-probe X-ray photoemission electron microscopy technique to determine the origin of the inertia. We find a clear inertia for the DW leading to a time lag between the field pulse and the reaction of the wall of 200 ps. By direct time-resolved magnetic imaging, we find that this is due to a change in the wall spin structure that stores exchange energy. This is caused by a transfer of Zeeman energy to exchange energy, for which the wall acts as a reservoir and this leads to an effective inertia of the wall (effective wall mass). We also see an oscillation of the DW around its equilibrium position after the excitation is switched off. Assuming a harmonic oscillator, an effective DW mass of 1.3· 10−24 kg± 1· 10−25 kg can be determined for the wall. This effective mass of our quasi particle is in line with results of micromagnetic simulations and with measurements that use transport techniques to determine the oscillation frequency.