Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 19: Mikro- und nanostrukturierte magn. Materialien I

MA 19.1: Vortrag

Montag, 7. März 2005, 10:30–10:45, TU EMH225

Depth-resolved investigation of the lateral magnetic correlations in polycristalline multilayers by reflectivity and off-specular scattering of polarized neutrons — •Emmanuel Kentzinger¹, Ulrich Rücker¹, Boris Toperverg¹, Frédéric Ott², and Thomas Brückel¹ — ¹Institut für Festkörperforschung, Forschungszentrum Jülich GmbH — ²Laboratoire Léon Brillouin, Saclay, France

The remagnetization process of a remanent magnetic multi-bilayer system with a gradient in the bilayer thicknesses was studied by reflectivity and off-specular scattering of polarized neutrons with polarization analysis performed on the HADAS reflectometer located at the research reactor FRJ-2 in Jülich. From the specular reflectivity, it is figured out that, by increasing the external magnetic field µ₀H, the magnetizations inside the ferromagnetic (FM) layers orient sequentially along µ₀H, from the bottom-most, thinnest FM layer to the top-most, thickest FM layer. This thickness dependency of the coercive field can be related to an evolution of the grain size. Also, the net magnetizations inside the FM layers that have not yet flipped have reduced magnitude with respect to their saturation value. The off-specular data lead to a more accurate description of the magnetization arrangement. They reveal that the reduced net magnetizations are a consequence of lateral fluctuations of both components of the magnetizations, perpendicular and parallel to µ₀H. Those interpretations are confirmed by simulations of the data in the framework of the Distorted Wave Born Approximation (DWBA).