A Study of Magnetic and Dielectric Properties for Iron Ion Variation in Cobalt Ferrite

Abstract

The influence of iron non-stoichiometry variation on structural, magnetic and dielectric properties in Cobalt ferrite is reported. Cobalt ferrite with compositional formula CoFe[Formula: see text]O4 ([Formula: see text], [Formula: see text]) was prepared through sol-gel synthesis route and sintered at 900oC/2[Formula: see text]h. X-ray diffraction confirms the phase evolution of ferrite with additional impurities belonging to [Formula: see text]-Fe2O3 phase and this additional phase disappears for iron deficient sample. The (311) peak shifts towards lower angle for the excess iron sample, whereas it shifts towards higher angle for iron deficient one, confirming the variation in the iron non-stoichiometry. Raman data substantiate the presence of vibrational bands assigned to metal ions in the cobalt ferrites. Change in the peak intensities and peak angle in Raman spectra clearly suggests the movement of cations among octahedral and tetrahedral sites leading to dilution of magnetic character of the samples. Saturation magnetization drastically drops by [Formula: see text]% for iron rich and deficient samples but an improvement in coercivity for the iron deficient cobalt ferrite clearly hints the role of anisotropy. A change in dielectric constant value further alludes to the change of iron ions in different valency states.