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Etude de couches minces magnétiques par réflectivité de neutrons polarisés. Diffusion hors spéculaire sur des structures périodiques.

Abstract : Theoretical (Zeeman energy effects) and experimental (beam polarisation problems) progress have been made in the understanding of polarized neutron reflectivity with polarisation analysis. It has been shown that modelisation and numerical simulations makes it possible to avoid to have to systematically measure a full set of reflectivity curves for each field and temperature condition. It has been possible to determine a magnetic profile as a function of the field in a magnetic bilayer system by using only a few points in the reciprocal space. This technique allows to considerably reduce the experiment time. In single nickel layer systems, we have shown that it is possible to induce magnetic rotation inhomogeneities when these systems are subjects to deformation strains. The effect are related to magneto-elastic constants gradients. In trilayer systems, with a ME constant modulation, we have been able to induce large magnetic rotation gradients. A new magneto-optic technique to mesure the magnetization direction without rotating the magnetic field has been developed. The field of neutron reflectivity has been extended to off-specular studies. It has been possible to accout quantitatively of the off-specular diffusion on 2D model systems (prepared by optical lithography). This new technique should make it possible in the future to determine magnetic structures with a in-depth as well as lateral resolution.
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https://tel.archives-ouvertes.fr/tel-00429503
Contributor : Frédéric Ott Connect in order to contact the contributor
Submitted on : Tuesday, November 3, 2009 - 10:58:20 AM
Last modification on : Monday, December 13, 2021 - 9:14:06 AM
Long-term archiving on: : Thursday, June 17, 2010 - 7:10:20 PM

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  • HAL Id : tel-00429503, version 1

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Frédéric Ott. Etude de couches minces magnétiques par réflectivité de neutrons polarisés. Diffusion hors spéculaire sur des structures périodiques.. Matière Condensée [cond-mat]. Université Paris Sud - Paris XI, 1998. Français. ⟨tel-00429503⟩

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