Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 23: Micro- and Nanostructured Magnetic Materials I

MA 23.4: Vortrag

Donnerstag, 29. März 2007, 11:00–11:15, H22

Magnetization Reversal of Microstructured Fe spirals — •Andreas Westphalen, Arndt Remhof, and Hartmut Zabel — Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany

A magnetic spiral structure (thickness: 20 nm, radius 2.8 µm, linewidth 100 nm) is used as a base for four different structure patterns. In contrast to a ring structure, in a spiral the magnetization cannot exhibit a closed flux configuration during the remagnetization process . Therefore, the process should prefer domain formation. The remagnetization processes in the spiral patterns are investigated with vector and Bragg MOKE in combination with micromagnetic simulations. We found that the magnetic reversal is the same in all four patterns. No notches, slits or other defects are introduced in the spiral which could influence the domain configuration during the magnetic reversal process. But the arrangement of the spiral patterns has an influence on the coercive field of the hysteresis curve. In the remanent state the micromagnetic simulations predict an onion-like state of the magnetization: the magnetization is divided at the horizontal axis, which is parallel to the applied magnetic field, in a lower and in an upper part where the magnetization follows the curvature of the spiral building magnetic poles at the horizontal axis. From the Bragg MOKE measurements we concluded that the switching process of the domains during the remagnetization is driven by domain wall movement.

We acknowledge financial support through SFB 491.