Influence of NiO concentration on structural, dielectric and magnetic properties of core/shell CuFe2O4/NiO nanocomposites

Nanocomposites of (1-x)CuFe2O4/xNiO (x = 10% to 50 wt %) have been synthesized utilizing a chemical co-precipitation method. In order to obtain the required phase, the samples have been annealed at 600 °C for 6 h. The x-ray Diffraction (XRD) technique has been used for the crystallographic structure analysis which not only confirms the coexistent of both copper ferrite (CuFe2O4) and nickel oxide (NiO) phases in all samples but also verifies the absence of any impurity phases. The average crystallite size as estimated via XRD patterns show that the average size lies in the range of 22-36 nm which has also been confirmed by TEM. The FTIR absorbance spectra also show the characteristic vibration modes of cation at tetrahedral and octahedral sites. The electrical properties like A.C. conductivity, impedance, Dielectric constant, and Tangent loss has been measured by LCR meter. The results show that with the increase in NiO concentration, electrical conductivity increases for all concentration while dielectric constant decreases up to 30% NiO wt% and increases with further addition of NiO. The real and imaginary parts of impedance depict same dispersion i.e the impedance decreases at higher frequency due to increase in conductivity. Moreover the magnetic characterizations performed by VSM, reveal that the hysteresis loops exhibit normal behavior of ferromagnetic/ferrimagnetic materials for all compositions but the coercivity (Hc), and saturation magnetization (Ms) decreases with the increase in NiO contents that transform the material in to soft magnetic.