Self-combustion synthesized NiFe2O4/reduced graphene oxide composite nanomaterials: Effect of chelating agent type on the crystal structure and magnetic properties

Ultrafine nickel ferrite and nickel ferrite/reduced graphene oxide nanocomposite materials have been synthesized by self-combustion method using glycine, citric acid and urea as chelating agent. The comparative analysis of structural and magnetic properties of the obtained materials in a temperature range of 300-900 degrees C has been performed. The changes in average particle sizes of spinel phase for NiFe2O4 and NiFe2O4/reduced graphene oxide materials have been analyzed from the point of view of the metalorganic complexes interaction and different mechanisms of gel formation for glycine, citric acid and urea based materials. The conditions of ferrimagnetic and superparamagnetic states formation of nickel ferrite nanoparticles have been investigated by Mossbauer spectroscopy. (C) 2019 Elsevier Ltd. All rights reserved.