Séminaire du Lundi 6 Février 2012 à 10h30

THE EFFECT OF PRESSURE ON MOLECULAR MAGNETISM

Alex PRESCIMONE (EastChemSchool of Chemistry – University of Edinburgh)

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de Conférence (401), 4ème étage, Tour 23, Couloir 22-23

 Résumé :

Clusters of paramagnetic metal ions have attracted intense study since
the discovery that such molecules can display the phenomenon of
single-molecule magnetism. The energy barrier to the relaxation of the
magnetisation implies a large ground state spin multiplicity (S) and a
significant zero-field splitting (D) of that ground state. The strength of
coupling and the magnitude of the zero-field splitting are governed by
the molecular geometry. The application of pressure can significantly
change the intra-molecular bond lengths, angles and, occasionally, the
connectivity: in-so-doing greatly modifies the observed magnetic
parameters.
Two ‘Mn6’ SMMs, hydroxo-bridged Cu dimers and Cu-based chains can
all be structurally and magnetically distorted by pressure. We describe
the combined crystallographic, magnetic and EPR experiments, all
performed at high pressure, on these materials.