High- T c Molecular-Based Magnets: Ferrimagnetic Mixed-Valence Chromium(III)-Chromium(II) Cyanides with T c at 240 and 190 Kelvin

Abstract

Molecular-based magnets with high magnetic-ordering temperatures, T_c, can be obtained by mild chemistry methods by focusing on the bimetallic and mixed-valence transition metal µ-cyanide of the Prussian blue family. A simple orbital model was used to predict the electronic structure of the metal ions required to achieve a high ordering temperature. The synthesis and magnetic properties of two compounds, [Cr₅(CN)₁₂].10H₂O and Cs_0.75 [Cr_2.125(CN)₆]·5H₂O, which exhibited magnetic-ordering temperatures of 240 and 190 kelvin, respectively, are reported, together with the strategy for further work.