Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)
MA 13.70: Poster
Dienstag, 9. März 2004, 15:00–19:00, Bereich A
Influence of point defects on magnetic vortex structures — •Michael Rahm1, Vladimir Umansky2, Werner Wegscheider1, and Dieter Weiss1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany — 2Braun Center for Submicron Research, Weizmann Institut, Rehovot 76100, Israel
Micro-Hall magnetometry represents a highly advanced experimental technique to measure hysteresis loops of individual ferromagnetic particles. Investigating submicron-sized Permalloy disks, it was shown that a magnetic vortex structure can be pinned at a lithographically defined point defect [1]. Here, we compare our Hall measurements with micromagnetic calculations based on LLG [2] in order to draw a detailed picture of the pinning process. By simulating the point defect simply as a hole in the disk, excellent agreement between experiment and calculation can be achieved, while more complex models of the defect result in larger deviations from the measurement. These investigations are crucial to understand the behavior of particles containing two or more defects. First results showing interesting multistable switching behavior in disks containing up to four defects are presented.
[1] M. Rahm, J. Biberger, V. Umansky, and D. Weiss, Vortex pinning at individual defects in magnetic nanodisks, J. Appl. Phys. 93 (10), 7429 (2003). [2] M. Scheinfein, see http://llgmicro.home.mindspring.com/