Phase transformation in Fe2O3 nanoparticles: Electrical properties with local electronic structure

Present work is focused on the study of various physical properties of different phases (α & γ) of Fe2O3 prepared just by varying initial precursors and solvents. Diverse structural and spectroscopic techniques infer growth of α-phase using gelatin (GEL) + deionized water (DI) while mixed (α & γ)phase is obtained with GEL + ethylene glycol (EG) as precursor and solvents in iron nitrate salt. By controlling the properties of the solvent media, we have been able to tune the crystallite size from 26.31 nm (α-phase) to 38.87 nm (mixed-phase). The corresponding activation energy for α-phase and mixed-phase was calculated using the Arrhenius plot. Dielectric loss and permittivity in both samples exhibited different behaviour with temperature and which can be explained based on their electronic structure studied by the X-ray absorption spectroscopy technique. The interplay of different phases of materials can be achieved just by controlling the synthesis parameters like solvents/precursors or both. •α- & γ-phased Fe2O3 nanoparticles were synthesized through sol-gel technique.•XRD, FTIR, XAS, and Raman spectroscopy revealed that the sample with GEL+DI would be α-Fe2O3 and the sample with GEL+EG would be γ-Fe2O3.•The activation energy was obtained from the plot of lnρ Vs 1000/T.•DC resistivity measurements with temperature indicate the semiconducting behavior of the samples.