Structural, EPR, optical and magnetic properties of α-Fe2O3 nanoparticles

α-Fe2O3 nanoparticles were synthesized by a low temperature solution combustion method. The structural, magnetic and luminescence properties were studied. Powder X-ray diffraction (PXRD) pattern of α-Fe2O3 exhibits pure rhombohedral structure. SEM micrographs reveal the dumbbell shaped particles. The EPR spectrum shows an intense resonance signal at g ≈ 5.61 corresponding to isolated Fe3+ ions situated in axially distorted sites, whereas the g ≈ 2.30 is due to Fe3+ ions coupled by exchange interaction. Raman studies show A1g (225 cm−1) and Eg (293 and 409 cm−1) phonon modes. The absorption at 300 nm results from the ligand to metal charge transfer transitions whereas the 540 nm peak is mainly due to the 6A1 + 6A1 → 4T1(4G) + 4T1(4G) excitation of an Fe3+–Fe3+ pair. A prominent TL glow peak was observed at 140 °C at heating rate of 5 °C s−1. The trapping parameters namely activation energy (E), frequency factor (s) and order of kinetics (b) were evaluated and discussed.

Packing diagram of α-Fe2O3 nanoparticles.Figure optionsDownload as PowerPoint slideHighlights
► Dumbbell shaped α-Fe2O3 nanoparticles with rhombohedral phase have been prepared.
► Spectroscopic investigations on α-Fe2O3 nanoparticles were carried out.
► From TL glow peaks trapping parameters were evaluated and discussed.