Berlin 2008 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 7: Micro and Nanostructured Magnetic Materials II
MA 7.9: Vortrag
Montag, 25. Februar 2008, 17:15–17:30, EB 301
Dipolar interactions on lateral structured square lattices — •Alexandra Schumann1, Arndt Remhof3, Andreas Westphalen1, Hartmut Zabel1, Torsten Last2, Ulrich Kunze2, Elena Vedmedenko4, and Nikolai Mikuszeit4 — 1Institut für Experimentalphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany — 2Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum, 44780 Bochum, Germany — 3EMPA, Hydrogen & Energy, Überlandstrasse 129, 8600 Dübendorf, Switzerland — 4Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11a, 20355 Hamburg, Germany
We investigated the remanent states of laterally structured permalloy dipole arrays. A single permalloy island has a length of L = 3 μm and a width of w = 0.3 μm. Due to the arrangement on a square lattice the magnetic dipoles are inherently frustrated and show different ground states depending on their separation. We implemented separations in the range of a = 0.42 μm to 3.4 μm. Theory predicts that for this geometry either an onion, a horseshoe or a vortex state may be realized in the remanent magnetic state. To achieve a vortex state a high energy barrier is required to overcome, therefore it is more likely to observe the onion or the horseshoe state. We could confirm these predictions of theory in our experiments by MFM images. Our experiments show that the remanent configuration of the dipoles depends on the direction of the initial magnetization as well as on the distance between the single elements.
This work was supported by the SFB 491 and the SFB 668.