Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 49: POSTER II
MA 49.13: Poster
Donnerstag, 19. März 2015, 15:00–18:00, Poster A
Formation of remanence states in permalloy rectangles investigated via magnetotransport and SEMPA — •Björn Beyersdorff1,2, Philipp Staeck2, André Kobs2, Mahmoud Reza Rahbar Azad2, Stefan Rößler2, Robert Frömter2, and Hans Peter Oepen2 — 1DESY, Notkestraße 85, 22607 Hamburg, Germany — 2INF, Universität Hamburg, Jungiusstr. 11a, 20355 Hamburg, Germany
Permalloy rectangles of 1000×500×20 nm3, structured by Focused Ion Beam milling, are investigated with Scanning Electron Microscopy with Polarization Analysis (SEMPA) and magnetotransport at room temperature. For these rectangles the well-known Landau, diamond and single domain C- and S-states are local minima of the energy landscape. By means of SEMPA we found that the remanence state can be tuned by varying the angle of a previously applied external saturation field within the film plane. The Landau state is only found for fields within an angle of α < 10∘ to the hard axis, while for angles α> 15∘ the C/S-state is found. This result can be understood with the help of micromagnetic simulations. An in situ magnetoresistance setup is used to further investigate the magnetization reversal [1]. The characteristics of the MR curves can be used to identify the remanence state and even allows to differentiate between the iso-energetic C-/S-states from symmetry arguments. Finally, it is shown that the observed variance of remanence states within nominally identical rectangles is due to structural variation, while stochastic influences of thermal activation are of minor importance. [1] A. Kobs et al., PRB 80, 134415 (2009).