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Microscopie tunnel à électrons balistiques: vers le Magnétisme

Abstract : The purpose of this work was to develop a ballistic electron emission microscopy (BEEM) set-up that could be used to study magnetic objects at the nanometer scale (magnetic domains and nanostructures imaging). We present in-depth calculations of macroscopic I(V) and BEEM Ib(V) spectra that are shown to prove very efficient for the analysis of experimental data. Before performing any microscopic measurements, the study of macroscopic I(V) characteristics provides crucial information about BEEM samples, namely the Schottky barrier height, the ideality factor and the resistance at zero voltage of the Schottky junction. Fits of BEEM spectra were calculated based on a model published by the pioneers of this technique which is described here in its progressive refinement stages. The development of a chemical process for the preparation of silicon substrate surfaces and clean room work are then reported. Samples elaborated by means of ultra high vacuum evaporation showed better characteristics than sputtered samples in terms of greater barrier height, better transmission and reduced noise. Different kinds of contrasts have been obtained from BEEM imaging. Some of them are directly linked to the attenuation for hot electrons depending on the thickness of the metallic layer whereas other contrast types clearly are different in nature and yet not completely understood. The issue of preparation and characterization of magnetic samples is also addressed.
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https://tel.archives-ouvertes.fr/tel-00080846
Contributor : Francois Caud <>
Submitted on : Friday, June 23, 2006 - 6:09:56 PM
Last modification on : Wednesday, September 16, 2020 - 4:32:35 PM
Long-term archiving on: : Monday, April 5, 2010 - 9:41:28 PM

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Francois Caud. Microscopie tunnel à électrons balistiques: vers le Magnétisme. Matière Condensée [cond-mat]. Université Paris Sud - Paris XI, 2006. Français. ⟨tel-00080846⟩

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