Giant magnetisation step in Fe₂: Molecular nanomagnets in the weak exchange limit

F. El Hallak (1, 2) , Patrick Rosa (3) , P. Vidal (4) , I. Sheikin (5) , M. Dressel (1) , Joris van Slageren (1, 6)

1 Pfaffenwaldring 57, D–70550 Stuttgart, Germany - Physikalisches Institut [Stuttgart]
2 London Centre for Nanotechnology
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
4 Institut für Theoretische Physik
5 GHMFL - Grenoble High Magnetic Field Laboratory
6 Institut für Physikalische Chemie [Stuttgart]

We investigate a Fe₂ molecular nanomagnet that displays a giant, field-induced step in its magnetisation curve. Detailed magnetisation and magnetic torque investigations demonstrate that in this Fe₂ system the single-ion anisotropy is dominant over the isotropic exchange coupling. Accurate spin Hamiltonian parameter values and tensor orientations are obtained. The theoretical analysis reveals that this system is a very promising candidate for the direct observation of the Néel vector tunnel splitting in weakly coupled molecular nanomagnets.

Mots clés: Molecular magnets; Magnetic anisotropy

Domaines: Matériaux

F. El Hallak, Patrick Rosa, P. Vidal, I. Sheikin, M. Dressel, et al.. Giant magnetisation step in Fe₂: Molecular nanomagnets in the weak exchange limit. EPL - Europhysics Letters, 2011, 95 (5), 57002 (5 p.). ⟨10.1209/0295-5075/95/57002⟩. ⟨hal-00619810⟩