Single phase MgFe 2 O 4 (MFO) ferrite was prepared through sol-gel auto-combustion route. The Rietveld analysis of X-ray patterns reveals that our samples are single phase. The increase in average particle size with annealing temperature and formation of nanoparticle agglomerates is observed in MgFe 2 O 4 . The structural morphology of the nanoparticles is studied using Scanning Electron Microscopy (SEM). Formation of spinel structure is confirmed using Fourier transform infrared spectroscopy (FTIR). The Zero-Field-Cooled (ZFC) and Field-Cooled (FC) magnetization measurements show the maximum irreversibility at 700 °C annealing temperature. The formation of a maximum at blocking temperature, T B ∼ 180 K for sample annealed at 500 °C in the ZFC curve shows the superparamagnetic behavior of the sample. The increase of saturation magnetism (M s ) may mainly result from the improvement of crystallinity and decrease of concentration of oxygen vacancies. Electrical properties were studied by ac conductivity, impedance and electric modulus measurements. The conduction in MFO is due to overlapping large polaron hopping mechanism.
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© 2017 Elsevier B.V.
- Polaron tunnelling
- Sol-gel processes
- X-ray diffraction