Study of thermal, structural, microstructural, vibrational and elastic properties of MnxMg0.8–xZn0.2Fe2O4 (0.1 ≤ x≤ 0.7) ferrite nanoparticles

Abstract

Sol-gel auto combustion method has been used to synthesize a series of MnxMg0.8–xZn0.2Fe2O4 (0≤ x ≤ 0.7 at a step of 0.1) nano ferrites. Thermogravimetric and Differential scanning calorimetry (TGA and DSC) studies revealed that the weight loss changes happened up to the temperature 700 °C. A stable ferrite phase without weight loss was found above 750 °C. XRD patterns gave the confirmation of cubic spinel phase of ferrite samples along with the minor amounts of α-Fe2O3 phase. The α-Fe2O3 phase appears to be increasing in the ferrite compositions for x ≥ 0.4. The experimental lattice parameter (a) and average crystallite size (<D>) are found to be in the range of 8.4205–8.4479 Å and 34.9–54.7 nm. A systematic variation was not found in both a and <D> with the substitution of Mn2+. FE-SEM micrographs do not provide individual particle sizes, but their nature showed the agglomeration of ferrite nanoparticles with magnetic interactions. The obtained higher and lower vibrational bands (υ1 and υ2) in FTIR spectra confirm spinel phase in support of XRD analysis. The ratio of bulk modulus to rigidity modulus (B/R) is greater than 1.75 for all ferrite compositions showing that the mechanical behaviour is ductile. The value of Poisson ratio (σ = 0.26) revealed the isotropic nature of ferrite compositions. Different parameters like cation distribution, substitution of Mn2+, configurational entropy, secondary phases and bond lengths are predominantly influencing the structural, vibrational and elastic properties of present ferrite compositions.