Interactions magnétiques dans des groupements binucléaires du Ruthénium +V

The cationic ordering in the BaM _{1}/{3}Ru_{2}/{3}O₃ (M = Mg, Ca, Cd, Sr) oxides which crystallize with the 6H structure gives rise to Ru ⁵⁺Ru ⁵⁺ pairs in (Ru ₂O ₉) clusters. The magnetic properties have been analyzed on the basis of the Heisenberg-Dirac-Van Vleck model: The d electrons are localized on each Ru ⁵⁺ ion and interact strongly through antiferromagnetic exchange. The susceptibility curves agree with the H.D.V.V. model. The values of the exchange integrals have been determined by fitting the experimental values.