Synthesis of nanocrystalline nickel ferrite by thermal decomposition of organic precursors

Abstract

Nickel ferrite powders were synthesized by thermal decomposition of the precursors obtained in the redox reaction between the mixture of Ni(NO3)2·6H2O and Fe(NO3)3·9H2O with polyalcohol: 1,4-butanediol, polyvinyl alcohol and also with their mixture. During this reaction the primary C–OH groups were oxidized at –COOH, while secondary C–OH groups at C=O groups. The carboxylic groups formed coordinate to the present Ni(II) and Fe(III) cations leading to carboxylate type compounds, further used as precursors for NiFe2O4. These precursors were characterized by thermal analysis and FT-IR spectrometry. All precursors thermally decomposed up to 350 °C leading to nickel ferrite weakly crystallized. By annealing at higher temperatures, nanocrystalline nickel ferrite powders were obtained, as resulted from XRD. SEM images have evidenced the formation of nanoparticulate powders; these powders present magnetic properties characteristic to the oxidic system formed by magnetic nanoparticles.