Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.47: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Hall micromagnetometry of magnetic vortices and single domain walls — •Lena Breitenstein, Peter Lendecke, René Eiselt, Ulrich Merkt, and Guido Meier — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany

Hall micromagnetometry is a powerful tool for the investigation of the magnetization of nanostructures. We apply the technique to study magnetic vortices [1] and domain-wall depinning [2] in Permalloy squares and wires. Both sample geometries are investigated in the temperature range between 1.6 and 50 K. In the square elements the vortex core is nucleated and driven through the sample by an external magnetic field. Because of the high sensitivity of the Hall sensor to the local stray fields we identify vortex core nucleation and displacement as well as minor loops. Thus the vortex state can be separated from other micromagnetic configurations. Furthermore we investigate the temperature dependence of the vortex core nucleation and displacement. In the wire geometry we examine the temperature dependence of depinning fields of single domain walls to gain knowledge about the pinning potential. The observations are well described by a model with a single energy barrier. Magnetic-force microscopy and micromagnetic simulations round out the low temperature experiments.

[1] M. Rahm, J. Stahl, W. Wegscheider, and D. Weiss, Appl. Phys. Lett. 85, 1553 (2004).

[2] P. Lendecke, R. Eiselt, U. Merkt, and G. Meier, submitted.