Solid solution of transition metal-dicarboxylates with tunable magnetic properties

Single crystals of inorganic-organic hybrid compounds, M-5(OH)(2)[CO2(CH2)(2)CO2](4) [M=Mn(Mn-s), Fe(Fe-s), Co(Co-s), Mn/Fe(Mn-Fe-n) and Mn/Co(Mn-Co-n)] were prepared under hydrothermal condition at 180degreesC from a mixture of transition metal(II) chlorides, succinic acid, potassium hydroxide, and water. Crystal structure of all compounds present the same structural type in the single-crystal X-ray diffraction refinements and X-ray powder diffraction analysis. The single crystal structural analyses for three homo-metallic compounds were performed and the prepared compounds have divalent metal ions on the basis of bond valence sum calculations. The unit cell constants for the hetero-metallic compounds, e.g., Mn/Fe, Mn/Co solid solutions were determined. Magnetic measurements show that the Mn-s may have antiferromagnetic interaction at low temperature. The Fe-s and the Co-s compounds have ferrimagnetic coupling below 10 K. The Mn-Co-n compounds show the ferromagnetic magnetic behavior while the Mn-Fe-n compounds present anti ferromagnetic ordering. (C) 2001 Editions scientifiques et. medicales Elsevier SAS. All rights reserved.