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Journal of Nanomaterials
Volume 2014, Article ID 416765, 7 pages
http://dx.doi.org/10.1155/2014/416765
Research Article

Structural, Optical, and Magnetic Characterization of Spinel Zinc Chromite Nanocrystallines Synthesised by Thermal Treatment Method

1Department of Physics, Faculty of Science, University Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
2Department of Physics, Faculty of Applied Science and Technology, Ibrahim Badamasi Babangida University, Lapai 234066, Nigeria

Received 18 June 2013; Revised 7 December 2013; Accepted 28 December 2013; Published 5 February 2014

Academic Editor: Claude Estournès

Copyright © 2014 Salahudeen A. Gene et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study reports the structural and magnetic characterization of spinel zinc chromite (ZnCr2O4) nanocrystallines synthesized by thermal treatment method. The samples were calcined at different temperatures in the range of 773 to 973 K. Polyvinylpyrrolidone was used to control the agglomeration of the nanoparticles. The average particle size of the synthesized nanocrystals was determined by powder X-ray diffraction which shows that the crystallite size increases from 19 nm at 773 K to 24 nm at 973 K and the result was in good agreement with the transmission electron microscopy images. The elemental composition of the samples was determined by energy dispersed X-ray spectroscopy which confirmed the presence of Zn, Cr, and O in the final products. Fourier transform infrared spectroscopy also confirmed the presence of metal oxide bands for all the samples calcined at different temperature. The band gap energy was calculated from UV-vis reflectance spectra using the Kubelka-Munk function and the band gap energy of the samples was found to decrease from 4.03 eV at 773 K to 3.89 eV at 973 K. The magnetic properties were also demonstrated by electron spin resonance spectroscopy, the presence of unpaired electrons was confirmed, and the resonant magnetic field and the of the calcined samples were also studied.