Solid state reaction synthesis of NiFe 2O 4 nanoparticles

Abstract

Ni-ferrite (NiFe 2O 4) nanoparticles have been synthesized via a solid state reaction process. Ni and Fe bi-metallic nanoparticles in the form of Ni 33Fe 67 alloy nanopowder are first synthesized by simultaneous evaporation of the required amounts of pure Ni and Fe metals followed by rapid condensation of the evaporated metal flux into solid state by means of an inert gas, helium, using the process of inert gas condensation (IGC). In order to form the NiFe 2O 4 structure, as-synthesized samples (Ni 33Fe 67) are annealed for 12 h in ambient conditions at different annealing temperatures. Structural analyses show that NiFe 2O 4 starts to form at around 450 °C and gets progressively well defined with increasing annealing temperatures yielding particle with size ranging between 15 and 50 nm. Besides successfully forming NiFe 2O 4, NiO/Fe 3O 4 core/shell nanoparticles have also been synthesized by adjusting the annealing conditions. Three different structures, Ni 33Fe 67, NiO/Fe 3O 4, and NiFe 2O 4, obtained in this study are compared with respect to their structural and magnetic properties.