Mössbauer and magnetization studies of nickel ferrite nanoparticles synthesized by the microwave-combustion method

Nanocrystalline nickel ferrite was synthesized from its stoichiometric metal nitrates and urea mixtures, using a microwave assisted combustion method. The process was a convenient, inexpensive and an efficient method for formation of NiFe2O4 nanomaterials. Effect of urea/metal nitrates ratio on the obtained phases, particle size and magnetic properties has been investigated by various techniques. Saturation magnetization of 50emu/g was observed at room temperature for larger particles, and it decreases with decreasing particle size. The coercivity attains a maximum value of 170Oe when the particle size was ~20nm, and decreases with increasing particle size. Mössbauer spectra measured at RT for some representative samples show a combination of ordered and superparamagnetic behavior, whereas those collected at 20K elucidate the nature of the obtained phases and cation distribution. •Nanosized Ni ferrite was synthesized by a microwave assisted combustion method.•The particle size was controlled by changing the urea/metal nitrate ratio.•Magnetization and coercive field vary with particle size.•Mössbauer spectra elucidate the nature of the phases and cation distribution.