Abstract of Publication No. 422
G. Chaboussant, R. Basler, A. Sieber, S. T. Ochsenbein, A. Desmedt, R. E. Lechner,
M. T. F. Telling, P. Kögerler, A. Müller and H. U. Güdel
We report an Inelastic Neutron Scattering (INS) study of the fully deuterated
molecular compound K6[VIV15As6O42]·9D2O
(V15). Due to geometrical frustration, the essential
physics at low temperatures of the V15 cluster
containing 15 coupled V4+ (S = 1/2) is determined by three weakly coupled spin-(1/2) on a triangle.
The INS spectra at low energy allow us to directly determine the
effective exchange coupling J0 = 0.211(2) meV within the
triangle and the gap 2D = 0.035(2) meV between the two spin-(1/2) doublets of the ground state. Results are
discussed in terms of deviations from trigonal symmetry and Dzyaloshinskii-Moriya (DM) interactions.