Skip to Main content Skip to Navigation
Theses

Intégration et mesures de magnéto-transport de nano-objets magnétiques obtenus par voie chimique

Julien Dugay 1
1 Nanomagnétisme (LPCNO)
LPCNO - Laboratoire de physique et chimie des nano-objets
Abstract : The study of charge transport in metallic and magnetic nano-objects chemically synthesized is a challenge in spintronic. Particularly, the lack of experimental results reveals the difficulty in locating such nano-objects in between electrodes while preserving their good properties. This thesis aims to overcome these difficulties in order to study the magnetotransport in such systems. Therefore, we have designed and developed technical processes which induce the self-assembly of the nano-objects inside a glove box-sputtering system. After studying the mechanisms involved in the self-assembly obtained by dip coating, we succeeded to deposit monolayers of nanoparticles (NPs) of different materials (FeCo, Fe, Co) on gold surfaces, SiO2 and thin resin film (40 nm). These results, coupled with a nanoindentation technique allows us to measure a few or a unique NP(s). Another technique, called dielectrophoresis, has been proved to be a simple and versatile way to trap (and align) nano-objects with different (aspect ratio), size, nature, and shape in between the electrodes. Thanks to this technique and the deposit of a protective capping layer of alumina, we studied the magnetotransport properties of a large number of nano-objects sensitive to oxidation or humidity: Fe, Co, FeCo and [Fe(H-trz)2(trz)](BF4)] (spin crossover compounds). Three sets of organic tunnel barriers surrounding different Fe NPs presented tunnel magnetoresistance up to room temperature. Moreover, [Fe(H-trz)2(trz)](BF4)] nano-objects with different aspect ratio, highlighted a change in conductance connected to the spin transition. Finally, we validated our ligands exchange methods by studying the influence of the ligands length on the conduction properties of Co NPs, which have been analyzed quantitatively. Our works demonstrate the possibility to use the chemical NPs in different fields of spintronics.
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00864511
Contributor : Julien Dugay Connect in order to contact the contributor
Submitted on : Monday, September 23, 2013 - 4:41:51 PM
Last modification on : Thursday, October 21, 2021 - 3:05:59 AM

Identifiers

  • HAL Id : tel-00864511, version 1

Citation

Julien Dugay. Intégration et mesures de magnéto-transport de nano-objets magnétiques obtenus par voie chimique. Chimie-Physique [physics.chem-ph]. INSA de Toulouse, 2012. Français. ⟨NNT : 2900651⟩. ⟨tel-00864511⟩

Share

Metrics

Record views

491

Files downloads

569