Magnetic and electric properties of nanoparticles of Ni-substituted ferrites synthesized using a microwave refluxing process

Microwave refluxing was found to be a suitable method to produce single phase magnetic nanoparticles of Ni Fe . Ethylene glycol employed in the synthesis plays a crucial role in restricting the particle size to nano dimensions. X-ray diffraction studies, Mössbauer spectroscopy and magnetic measurements suggest that as-prepared samples were small in size (∼15 nm) and hence display low saturation magnetization values (44–60 emu g ). Ni Fe transforms into γ-Ni Fe and α-Ni Fe after sintering at 720 and 1020 K respectively as indicated by X-ray diffraction patterns. This was also confirmed by resistivity measurements. The electrical properties of the two transformed phases were comparable to their bulk values. It has also been found that a large substitution of Ni stabilizes γ-phase at higher temperature.