Materials Chemistry and Physics, Vol.131, No.1-2, 413-419, 2011
Structural and vibrational properties of ZnxMn1-xFe2O4 (x=0.0, 0.25, 0.50, 0.75, 1.0) mixed ferrites
In this paper, we report the variations in the crystal structure, average crystallite size, Raman spectra and magnetic properties of ZnxMn1-xFe2O4 (x = 0.0, 0.25, 0.5, 0.75, 1.0) mixed ferrite samples synthesized by chemical co-precipitation method. The X-ray diffraction pattern confirms that the mixed ferrite samples are in cubic inverse spinel structure, which is further validated by Rietveld refinement. The oxygen position, the lattice parameter, and the cation distribution have been determined by means of Rietveld analysis, indicating the existence of mixed ferrites in all samples. The final structure was refined in space group Fd3m. The structural studies identify the decrease of lattice parameter, whereas the crystallite size increases and porosity decreases on increasing the Zn concentration. IR spectra confirm vibration of Fe2+-O2- bond at tetrahedral (A) site. The Raman spectrum reveals active phonon modes at room temperature and shifting of modes toward the higher frequency side on moving from MnFe2O4 to ZnFe2O4. The transmission Mossbauer spectroscopy determines the site preference of the substituted ions and their effect on the hyperfine magnetic fields. The results showed that all the samples are superparamagnetic in nature. (C) 2011 Elsevier B.V. All rights reserved.