Partenaires

CNRS Universite Grenoble Alpes UPS LaNEF INSA TOULOUSE EMFL NEXT

Home


Home page > Research activities > Molecular magnetism > For further information > Introduction

Français

Introduction

Principles  

The research activity of the team is focused on electron spin resonance in high field and high frequency (HF-EPR) and synthesis of molecule-based magnetic materials.
 

HF-EPR
 
For the HF-EPR, the effects related to high field can usually be distinguished from those associated with high frequency:

- The main interest for using high fields concerns systems that have a X band signal. These studies focus on systems with spin S = 1 / 2. They allow measuring differences in Landé factors masked at low-field system by either excessive linewidths, or field-independent interactions such as hyperfine ones.

- The high frequency measurements mainly applies to the study of the so-called ‘X-band silent’ compounds, that is to say to compounds with integer spin and/or large zero-field splitting (ZFS). The development of EPR spectrometers using high frequencies (95 GHz and above) in fact led to the disappearance of the concept of EPR silent compound.

Chemical synthesis 
The synthesis of molecular magnetic materials is mainly developed along two axes that shall feed one another:

- The synthesis and study of multifunctional magnetic materials. It is based on the versatility of molecular chemistry. It indeed allows, by an appropriate choice of the starting precursors, to obtain materials combining several physico-chemical properties in a rational way. In the most interesting cases, these properties interact to give rise to new physico-chemical properties. Our efforts are currently orientated towards compounds combining magnetism and properties associated with non-centrosymmetry.

- The synthesis and study of magnetic materials based on verdazyl radical. These organic species give birth to purely organic compounds of interest but are also the source for developing an original coordination chemistry leading to compounds where the exchange interaction can be very strong. The richness of the interactions found in these two families of compounds raises fundamental questions about the basic concepts of molecular magnetism. We try to
answer to these question through a comprehensive approach that combines synthesis, characterization and theoretical calculations.

 
Main topics 

• Mn (III), Ni (II), V (III), Fe (II) and Ln(III) mononuclear complexes with integer spin and large ZFS (’EPR silent’) 

 

• clusters of spins, especially ’single molecule magnets’ (molecules with large spin in the ground state and negative ZFS)
• dinuclear complexes of Mn with small coupling: studies of the different spin states
• radicals with low Zeeman anisotropy: tyrosinyle, glycinyle, verdazyle
• oxalate-bridged compounds
• verdazyl, oxoverdazyl and thiooxoverdazyl radicals-based compounds