Structural and electron spin resonance spectroscopic studies of MnxZn1−xFe2O4 (x = 0.5, 0.6, 0.7) nanoferrites synthesized by sol-gel auto combustion method

Abstract

Nanoferrites with the chemical equation MnxZn1−xFe2O4 (x = 0.5, 0.6, 0.7) were prepared by sol-gel auto combustion method in order to study their structural, elastic and electron magnetic resonance properties. The Bragg reflections in the X-ray diffractograms matched with the formation of cubic spinel phase along with the secondary phases of α-Fe2O3 and Mn2O3. The uneven variation of lattice parameter was found to be depending on the possible cation redistribution in the spinel structure/or grain sizes. From the histograms of SEM studies, the composition x = 0.6 comparatively has a narrow distribution of grain sizes (5–11 μm) than those of compositions x = 0.5 (3.5–8.5 μm) and x = 0.7 (2.5–8.5 μm). The higher and lower vibrational frequencies in the FTIR spectra occurred around 560 cm−1 and 470 cm−1 confirm the cubic spinel phase of present ferrite systems in the line of XRD confirmation. The change in the vibrational frequencies supports the variation of lattice parameter. The variation of lattice energy is supportive for the elastic properties, but not to the structural parameters. The same value of Poisson’s ratio (∼0.35) for the three compositions is an indicative, representing the isotropic behaviour of spinel ferrite systems. The range (2.012–2.106) of Lande’s g-parameter indicates the change in Fe3+–O–Fe3+ superexchange interaction. The results are interpreted based on the possible cation redistribution, the secondary phases presuming the core-shell interactions.