Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 9: Hauptvortrag Theis-Bröhl

MA 9.1: Hauptvortrag

Dienstag, 25. März 2003, 09:30–10:00, HSZ/04

Magnetisation reversal of stripe arrays - A study by polarized neutron reflectivity — •Katharina Theis-Bröhl — Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum

Laterally structured magnetic films are important components of future magnetic storage elements. From the aspect of application, remagnetization within a one domain state is preferred. However, in order to minimize stray field energies, lateral structures often form domains. Therefore, the study of the remagnetization process is of particular interest and was performed by polarized neutron reflectivity (PNR) at CoFe stripe arrays. The results are compared to magneto-optic Kerr effect and Kerr-microscopy. PNR is a method which can distinguish between magnetization reversal via coherent rotation or domain nucleation and wall movement. By applying PNR to lateral structures it is possible to perform remagnetization measurements at the specular reflection and at Bragg peaks from the artificial periodicity of the lateral structure. Whereas, at the specular reflection, an averaged signal over the complete sample is measured, the Bragg peaks filters out correlation effects between individual magnetic units. The parameters of the CoFe stripes were chosen in such a way that a strong two-fold shape anisotropy is present. When increasing the width of the stripes, the anisotropy changes and more complex domain configurations are observed during the magnetization process. From PNR, MOKE and Kerr microscopy we find indications for dipole-dipole interaction between the stripes. We acknowledge funding by DFG, SFB 491 and BMBF 032AE8BO.