Moessbauer studies on the thermolysis of manganese tris(malonato)ferrate(III)hexahydrate

The thermal decomposition of manganese tris(malonato)ferrate(III) hexahydrate, Mn3[Fe(CH2C2O4)3]2 x 6H2O has been investigated from ambient temperature to 600 deg C in static air atmosphere using various physico-chemical techniques, i.e., simultaneous TG-DTG-DSC, XRD, Moessbauer and IR spectroscopic techniques. Nano-particles of manganese ferrite, MnFe2O4, have been obtained as a result of solid-state reaction between α-Fe2O3 and MnO (intermediate species formed during thermolysis) at a temperature much lower than that for ceramic method. SEM analysis of final thermolysis product reveals the formation of monodisperse manganese ferrite nanoparticles with an average particle size of 35 nm. Magnetic studies show that these particles have a saturation magnetization of 1861G and Curie temperature of 300 deg C. Lower magnitude of these parameters as compared to the bulk values is attributed to their smaller particle size. (author)