A study of nanosized magnesium ferrite particles with high magnetic moment

•Highest magnetisation (M) among nano sized magnesium ferrite particles was obtained.•The obtained magnetisation was nearly double of furnace cooled bulk sample.•Coercivity (Hc) is anti correlated to M for samples with different heat treatment.•Coefficient of non saturation of magnetisation in M–H loop (a), is correlated with Hc.•Hc, M and a are explained in terms of cation distribution obtained using NNéel model.

Nano-sized magnesium ferrite particles were prepared by sol gel combustion synthesis and were either furnace cooled or quenched after calcining at various temperatures ranging from 300 to 800 °C. A magnetisation value of 61 emu/g was obtained at 5 K for sample calcined at 800 °C and quenched in liquid nitrogen temperature. This is one of the highest reported values of magnetisation obtained from quenching at such a lower temperature. An estimate of the number of Fe3+ ions on A and B sites was made after applying Néel Model on the magnetisation values measured at 5 K. It was estimated that Fe3+ ions segregates out from both sites disproportionately so as to cause a net decrease in the overall moment. The resultant cation distribution is found to be consistent with the coercivity data.