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Etude structurale et magnétique de systèmes Fe/Mn

Abstract : This thesis is focused on the preparation and microstructural / magnetic characterization of exchange-biased Fe/Mn multilayers. The structural characterization was performed by transmission electron microscopy, which enabled the structures to be identified as α-Fe and α-Mn. It also evidenced the evolution of roughness at the interfaces as a function of the deposition temperature. Atom probe tomography allowed a local analysis of the interfaces. The linear concentration profiles obtained revealed an asymmetry of the Fe/Mn and Mn/Fe interfaces as well as the formation of an Fe-Mn alloy with a modulated concentration at the interfaces. It was found that the width of the Fe/Mn interface increases with increasing deposition temperature. Mössbauer spectroscopy measurements probed the local environment of Fe atoms. The Fe-rich areas are ferromagnetic with a hyperfine field distribution reflecting the modulated composition, and the Mn-rich areas are antiferromagnetic with a Néel temperature very close to that of α-Mn. The magnetic characterization was carried out primarily by SQUID magnetometry, which allows the net magnetization, exchange field and coercive field to be determined. Besides, the magnetization depth profiles were obtained by polarized neutron reflectometry which identified two types of Fe layers, and showed the influence of the growth temperature on the coercive field.
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https://tel.archives-ouvertes.fr/tel-00688107
Contributor : Anouar El Bahoui <>
Submitted on : Monday, April 16, 2012 - 5:14:04 PM
Last modification on : Thursday, May 16, 2019 - 1:18:02 PM
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  • HAL Id : tel-00688107, version 1

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Anouar El Bahoui. Etude structurale et magnétique de systèmes Fe/Mn. Science des matériaux [cond-mat.mtrl-sci]. Université de Rouen, 2011. Français. ⟨tel-00688107⟩

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