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

Jahagirdar, AA and Dhananjaya, N and Monika, DL and Kesavulu, CR and Nagabhushana, H and Sharma, SC and Nagabhushana, BM and Shivakumara, C and Rao, JL and Chakradhar, RPS (2013) Structural, EPR, optical and magnetic properties of alpha-Fe2O3 nanoparticles. In: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, 104 . pp. 512-518.

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Official URL: http://dx.doi.org/ 10.1016/j.saa.2012.09.069

Abstract

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. (C) 2012 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, ENGLAND.
Keywords: Nanostructures; Chemical synthesis; Crystal structure; Electron microscopy; Luminescence
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Depositing User: Francis Jayakanth
Date Deposited: 10 Apr 2013 06:55
Last Modified: 10 Apr 2013 06:55
URI: http://eprints.iisc.ac.in/id/eprint/46316

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