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

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 Mossbauer 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.