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

作者：Jahagirdar A A; Dhananjaya N; Monika D L; Kesavulu C R; Nagabhushana H^*; Sharma S C; Nagabhushana B M; Shivakumara C; Rao J L; Chakradhar R P S

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2013, 104: 512-518.

DOI：10.1016/j.saa.2012.09.069

• Nanostructures
• Chemical synthesis
• Crystal structure
• Electron microscopy
• Luminescence

alpha-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 alpha-Fe2O3 exhibits pure rhombohedral structure. SEM micrographs reveal the dumbbell shaped particles. The EPR spectrum shows an intense resonance signal at g approximate to 5.61 corresponding to isolated Fe3+ ions situated in axially distorted sites, whereas the g approximate to 2.30 is due to Fe3+ ions coupled by exchange interaction. Raman studies show A(1g) (225 cm(-1)) and E-g (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 (6)A(1) + (6)A(1) --> T-4(1)(4G) + T-4(1)(4G) excitation of an Fe3+-Fe3+ pair. A prominent TL glow peak was observed at 140 C at heating rate of 5 degrees C s(-1). The trapping parameters namely activation energy (E), frequency factor (s) and order of kinetics (b) were evaluated and discussed.

• 出版日期2013-3