On the basis of initial studies indicating that an increased stoichiometry of vanadium(II) led to a higher Curie temperature in vanadium hexacyanochromate systems, Ohkoshi et al. used a small amount of VIII as catalyst to convert a higher proportion of VII in a similar system. The magnetic properties of the resulting octacyano-bridged vanadium–niobium bimetal assembly were investigated. The compound, whose formula was determined to be K0.59VII1.59VIII0.41[NbIV(CN)8] ·(SO4)0.50·6.9H2O, is ferrimagnetic, and the spins on VII and VIII are antiparallel with respect to the spin on NbIV. Its Curie temperature is 210 K. This high value is a result of the enhanced superexchange interaction through the VII–NC–NbIV pathway.
This study reports a strategy to synthesize magnetic materials with high Curie temperature to enhance the suitability of their magnetic properties for applications.
More information: Shin-ichi Ohkoshi, A Cyano-Bridged Vanadium–Niobium Bimetal Assembly Exhibiting a High Curie Temperature of 210 K, European Journal of Inorganic Chemistry, http://dx.doi.org/10.1002/ejic.201101219
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