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Autori: Chirtop, E. , Mitov, I. , Ion, R.M. , Iliescu, M.
Editorial: Journal of Optoelectronics and Advanced Materials, 2(4), p.379-384, 2000.
Ultrafine cobalt ferrite has been prepared by the decomposition of cobalt oxalate-hydrazinate complex, which is used as precursor. The preparation and thermal decomposition of the precursor have been studied using chemical, thermal, and infrared techniques. The precursor decomposes at low temperatures with the effusion of large amounts of gases. The coordination compounds used as chemical precursors have to include, ligands, which generate, by decomposition, volatile products. Carboxylic acids are ligands, which correspond to this requirement. It is well known that the time required for thermal decomposition of oxalates can be considerably shortened if the precursors are heated in the presence of a reducing agent, such as hydrazine. The hydrazine together with cobalt cations have been incorporated in the structure of iron oxalate for yielding coordination compounds, chemical precursors for low temperature synthesis of the corresponding ferrite. For cobalt oxalate-hydrazinate it was established the chemical composition, spectral properties and thermal behaviour to determine the conditions for ferrite powder synthesis. Chemical, infrared, and Mossbauer spectroscopy confirmed the formation of spinelic ferrite, at 500 °C.
Cuvinte cheie: Co-Fe oxalate-hydrazinate; Ferrite powder; Inverse spinelic ferrite; Low temperature