Mechanism of ground-state selection in the frustrated molecular spin clusterG. Chaboussant1, S. T. Ochsenbein1, A. Sieber1, H.-U. Güdel1, H. Mutka2, A. Müller3 and B. Barbara4
1 Department of Chemistry, University of Bern - CH-3000 Bern 9, Switzerland
2 Institut Laue-Langevin - BP 156, 38042 Grenoble, France
3 Department of Chemistry, University of Bielefeld - 33501 Bielefeld, Germany
4 Laboratoire de Magnétisme Louis Néel, CNRS - BP 166, 38042 Grenoble, France
(Received 5 January 2004; accepted in final form 23 February 2004)
We report an inelastic neutron scattering (INS) study under a magnetic field on the frustrated molecular spin cluster V15. Several field-dependent transitions are observed and provide a comprehensive understanding of the low-energy quantum spin states. The energy gap between the two lowest S=1/2 Kramers doublets is unambiguously attributed to a symmetry lowering of the cluster. The INS data are mapped onto an S=1/2 Antiferromagnetic Heisenberg triangle with scalene distortion. A quantitative description of the wave function mixing within the ground state is derived.
75.30.Et - Exchange and superexchange interactions.
75.50.Xx - Molecular magnets.
78.70.Nx - Neutron inelastic scattering.
© EDP Sciences 2004