Influence of Mn substitution on crystal structure and magnetocrystalline anisotropy of nanocrystalline Co1 x Mn x Fe2 2x Mn2x O4

Nanocrystalline Mn substituted cobalt ferrite Co1 x Mn x Fe2 2x Mn2x O4 (x = 0.0–0.4) has been synthesized by the standard citrate–gel method. The structural and magnetic characteristics of all samples have been studied using powder X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM) and VSM techniques. Distributions of cations between the two interstitial sites (tetrahedral and octahedral site) have been estimated qualitatively by analyzing the powder X-ray diffraction patterns by employing the Rietveld refinement technique. All samples are found to be mixed spinel with cubic structure ( $ Fd\mathop 3\limits^{ - } m $ space group). The FT-IR study shows the presence of absorption bands in the range of 390–750 cm 1, which confirm the spinel structure of the sample. The stoichiometry of Co, Fe, Mn and O ions in the sample has been obtained by using energy-dispersive spectrum with help of an FE-SEM. The magnetizations in saturation have been analyzed by employing the “law of approach” technique. The saturation magnetization, coercivity and magnetocrystalline anisotropy constant depend upon Mn ion concentration and crystallite size.