Cation distribution in Ni-substituted Mn0.5Zn0.5Fe2O4 nanoparticles: A Raman, Mössbauer, X-ray diffraction and electron spectroscopy study

•Synthesized Mn0.5−xNixZn0.5Fe2O4, nanoparticles (0.05≤x≤0.45) at low temperature.•Raman studies established that Fe and Zn ions occupy A site in equal fraction.•57Fe Mossbauer study revealed that Ni and Mn ions occupy nearly 25% of B sites.•Electron spectroscopy (XPS) confirmed that nearly 25% Fe3+ dwells at A sites.•Diffraction peak intensity (X-ray) quantified cations distribution at A- and B-sites. In this paper we report the structural, vibration, and electronic-structure parameters (bonding and valence of cations) of single phase cubic mixed spinel nanoparticles of (ZnδMnγFe1−(γ+δ))[NixZn0.5−δMn0.5−γ−xFe1+(γ+δ)]O4 where x=0.05–0.45 with an aim to determine cation-distribution i.e. δ and γ in these samples. The Raman spectroscopy has established that only Fe and Zn cations occupy tetrahedral interstitial sites in a FCC anion lattice in nearly equal fraction, and Mössbauer spectra have shown that Fe3+ cations are present at both, tetrahedral and octahedral interstitial sites and Ni2+ cations are situated at the octahedral sites in all the substituted samples. The photoelectron spectra also revealed the presence of Fe3+ cations at both the interstitial sites. The best possible cationic distribution in Ni substituted Mn–Zn ferrites has been estimated by reiteratively calculating the intensity ratios of various pairs of X-ray diffraction peaks and matching with the observed intensity ratios.