Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Micro- and Nanostructured Magnetic Materials I
MA 23.5: Vortrag
Donnerstag, 29. März 2007, 11:15–11:30, H22
Longitudinal Bragg- and Vector-MOKE investigation on the rotational sense of vortices in Permalloy Nanodots — •Min-Sang Lee1, Andreas Westphalen1, Arndt Remhof1, Alexandra Schumann1, Thorsten Last2, Ulrich Kunze2, and Hartmut Zabel1 — 1Institut für Experimentalphysik IV (Festkörperphysik), Ruhr-Universität Bochum, 44780 Bochum — 2Institut für Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum, 44780 Bochum
We have used the Bragg-MOKE technique in longitudinal geometry (L-MOKE) for the first time to study the rotational sense of vortices in Py nanodots. The dots were shaped such that only one uniqely defined rotational sense was present in the whole dot array. Due to the fact that the rotational sense manifests itself in the sign of the imaginary part of magnetic form factors, we have been able to show that the rotational sense can be extracted from the hysteresis loops recorded for positive and negative diffraction order. We have also developed a formalism describing the relation between the magnetic form factor and the Bragg-MOKE signal. This theoretical work has been needed because there is no such formalism regarding the L-MOKE applied to dot arrays. The validity of our formalism is tested by comparsion with the measurement results on the Py dots, which shows a good agreement. We conclude that the L-MOKE is an eligible method for studying the rotational sense of vortices. This work was financially supported by the SFB 491.