Inelastic neutron scattering has been used to determine the anisotropic spin Hamiltonian that splits the S = 10 ground multiplet of the cluster (tacn)(6)Fe8O2(OH)(12)Br-4.3(ClO4)(3.7)6H(2)O (Fe8PCl), where (tacn) is the organic ligand 1,4,7-triazacyclononane. This single-molecule magnet,which is obtained from the well known Fe8Br Cluster, by partial replacement of the bromide ions by perchlorate anions, presents a larger transverse anisotropy than the parent compound, the E/D ratio being 0.22 instead of 0.16. This is in agreement with the relaxation measurements in the pure quantum tunneling regime. The details of the neutron spectra detected at three different temperatures (2, 10, and 15 K) allowed us to determine the spin Hamiltonian parameters up to fourth order and to identify the main source of the transition linewidth broadening with the occupational disorder of the bromide and perchlorate ions, rather than with the random internal dipolar field distribution.
Neutron transitions within the S=10 ground multiplet of a Fe-8 magnetic cluster / Carretta S.; Liviotti E.; Amoretti G.; Caciuffo R.; Caneschi A.; Gatteschi D.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - STAMPA. - 65:(2002), pp. 052411-052411. [10.1103/PhysRevB.65.052411]
Neutron transitions within the S=10 ground multiplet of a Fe-8 magnetic cluster
CANESCHI, ANDREA;GATTESCHI, DANTE
2002
Abstract
Inelastic neutron scattering has been used to determine the anisotropic spin Hamiltonian that splits the S = 10 ground multiplet of the cluster (tacn)(6)Fe8O2(OH)(12)Br-4.3(ClO4)(3.7)6H(2)O (Fe8PCl), where (tacn) is the organic ligand 1,4,7-triazacyclononane. This single-molecule magnet,which is obtained from the well known Fe8Br Cluster, by partial replacement of the bromide ions by perchlorate anions, presents a larger transverse anisotropy than the parent compound, the E/D ratio being 0.22 instead of 0.16. This is in agreement with the relaxation measurements in the pure quantum tunneling regime. The details of the neutron spectra detected at three different temperatures (2, 10, and 15 K) allowed us to determine the spin Hamiltonian parameters up to fourth order and to identify the main source of the transition linewidth broadening with the occupational disorder of the bromide and perchlorate ions, rather than with the random internal dipolar field distribution.File | Dimensione | Formato | |
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