Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: Spin-Dynamics/Switching I
MA 19.5: Vortrag
Mittwoch, 28. März 2007, 16:15–16:30, H23
Direct observation of the out-of-plane vortex core magnetization — K.W. Chou1, A. Puzic1, •H. Stoll1, D. Dolgos1, M. Curcic1, B. Van Waeyenberge2, A. Vansteenkiste2, T. Tyliszczak3, G. Woltersdorf4, C.H. Back4, and G. Schütz1 — 1MPI für Metallforschung, Stuttgart — 2Dep. of Subatomic and Radiation Physics, Ghent University — 3Advanced Light Source, Berkeley, CA — 4Inst. für Exp. und Angew. Physik, Univ. Regensburg
The vortex core, which plays a key role in magnetic vortex dynamics, was investigated by time-resolved scanning transmission X-ray microscopy. Reversal of the vortex core by excitation with short bursts of an in-plane alternating field was discovered recently [1]. This allows dynamic switching of the vortex core polarization with a one-period magnetic field burst as low as 1.5 mT, in contrast to (static) out-of-plane fields of half a Tesla needed so far. Micromagnetic simulations enabled us to explain this novel switching scheme by creation of a vortex-antivortex pair with opposite polarization in respect to the original vortex and annihilation of the antivortex with the original vortex. At the end a vortex with opposite polarization remains [1]. By improving our experiments we now are able to directly observe the reversal of the out-of-plane magnetization of the vortex core rather than monitoring a change in the sense of gyration. In addition, a strong distortion was observed in the spin distribution of the moving vortex core with an asymmetry in the motion for a core pointing up and down respectively.
[1] B. Van Waeyenberge, A. Puzic, H. Stoll, K. W. Chou et al., Nature 444, 461 (2006)