Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Micro- and Nanostructured Magnetic Materials I
MA 23.2: Vortrag
Donnerstag, 29. März 2007, 10:30–10:45, H22
TEM investigations of the magnetization patterns of sagged Permalloy microstructures — •Christian Dietrich1, Michael Huber1, Dieter Weiss1, Josef Zweck1, and Riccardo Hertel2 — 1Institut für Experimentelle und Angewandte Physik der Universität Regensburg, Germany — 2Forschungszentrum Jülich, Germany
For Lorentz transmission electron microscopic investigations of patterned magnetic specimens, the electron beam has to transmit the sample. Therefore the specimens are usually grown onto thin Si3N4 membranes. Due to mechanical tension the magnetic layers are not perfectly flat but sagged. Performing AFM measurements we found that the topography of the specimens is in a good approximation paraboloidally sagged with the center about 20-30 nm below the edges (for a micron sized specimen). When only in-plane magnetic fields are applied, the magnetization pattern behaves as expected for flat specimens. However, when an out-of-plane magnetic field is applied, the magnetization patterns change remarkably. For Permalloy squares with Landau domain structure the domain walls bend while for disks the vortex displacement due to an applied in-plane field deviates from the usual behaviour. The results can be explained by energy considerations and are of importance in the investigation of vortex motion, when perpendicular magnetic fields are present. Once more, the sensitive reaction of micromagnetic patterns on the specimen’s geometry is confirmed.