Skip to Main content Skip to Navigation
Theses

Organisations d'aimants moléculaires au sein de réseaux inorganiques et de coordination : synthèse, structure et propriétés.

Abstract : With the constant increase of data volume, the storage of information became an important issue. In this field of research, the discovery of coordination complexes behaving like traditional magnets really aroused a great deal of interest. These molecular magnets (Single-Molecule Magnet or Single-Chain Magnet) show magnetic hysteresis and thus a memory effect opening the possibility to address one bit of information on a single molecular object. Therefore, the design of new materials with original physical properties based on molecular magnets became the focus of many researches around the world. The use of these magnetic objects for future applications in technological devices is also a major trend of research. In this context, the work presented here includes these two aspects. A first part is dedicated to the one-dimensional organisation of molecular magnets into mesoporous silicas (MCM-41 and SBA-15 types). Our results clearly demonstrate all the difficulties to prepare and to study such magnetic hybrid materials. We showed that manganese-based single-molecule magnets are destroyed during their insertion into mesoporous silica. However, the use of a new synthetic protocol and a detailed characterization of these hybrid materials give encouraging results and open new perspectives for future researches in this field. The second part discusses the synthesis of new molecular magnets and their use to form 1D and 2D coordination networks. The employed strategy led to new molecular magnets that display rare quantum phenomena such as "quantum phase interference" or "exchange-bias quantum tunnelling". Also seven one-dimensional networks and two twodimensional materials were synthesized. Three of these one-dimensional networks composed of antiferromagnetically coupled single-molecule magnets, show very interesting and unique magnetic properties. For the first time, slow relaxation of magnetisation was observed in this type of one-dimensional compounds. In addition, the analysis of their magnetic relaxation clearly highlighted the polydispersity in term of chain length. The preliminary magnetic study of the other single-molecule magnets based materials reveals that they possess original properties.
Complete list of metadatas

Cited literature [35 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00583108
Contributor : Nadine Laffargue <>
Submitted on : Monday, April 4, 2011 - 5:12:09 PM
Last modification on : Thursday, January 11, 2018 - 6:15:00 AM
Long-term archiving on: : Tuesday, July 5, 2011 - 2:44:04 AM

Identifiers

  • HAL Id : tel-00583108, version 1

Collections

Citation

Lollita Lecren. Organisations d'aimants moléculaires au sein de réseaux inorganiques et de coordination : synthèse, structure et propriétés.. Matériaux. Université Sciences et Technologies - Bordeaux I, 2006. Français. ⟨tel-00583108⟩

Share

Metrics

Record views

494

Files downloads

538