Laboratoire Léon Brillouin
UMR12 CEA-CNRS, Bât. 563 CEA Saclay
91191 Gif sur Yvette Cedex, France
+33-169085241 llb-sec@cea.fr
Ana Borta, Béatrice Gillon, Arsen Gukasov, Alain Cousson, Dominique Luneau, Erwann Jeanneau, Iurii Ciumacov, Hiroshi Sakiyama, Katsuya Tone, and Masahiro Mikuriya
Polarized neutron diffraction investigations of a paramagnetic molecular dinuclear Co2+ complex, using the local site susceptibility method, show that the Co2+ ions carry opposite magnetic moments of 3.1(1) and 3.2(1) μB, making an angle of 37(1)° which is in agreement with the value (39°) provided by the theoretical analysis of the magnetic susceptibility using the model of effective spin ½. Polarized neutron diffraction (PND) shows that this dinuclear Co2+ complex behaves more like a system of two antiferromagnetically coupled ions with spin 3/2, the directions of which are imposed by the distortion axis of the octahedra around each Co2+ ion due to ligand field. This first application of the local susceptibility tensor method to a molecular compound demonstrates the efficiency of the PND method as a tool for exploring magnetic anisotropy in molecular paramagnets.