M. Aebersold, H. P. Andres, H. Büttner, J. J. Borrás-Almenar, J. M. Clemente, E. Coronado, H. U. Güdel and D. Kaerly
Magnetic excitations in polyoxometalate tetrameric clusters
Physica B 234-236, 764-765 (1997)                 

Abstract: The metal-oxide clusters with formula [M₄(D₂O)₂(PW₉O₃₄)₂]^10- which contain a tetrameric magnetic cluster M₄O₁₆ provide an ideal series for the study of magnetic exchange interactions in polymetallic molecular clusters. To get a more direct information on the splitting of the spin states caused by the exchange interactions we have performed inelastic neutron scattering measurements on the Co, Mn and Ni clusters. Magnetic excitations have been observed in the range 0.5-6 meV. A tentative interpretation of these data from a Heisenberg exchange Hamiltonian and a single ion zero-field splitting is presented for Ni cluster.