Structural, optical, and dielectric properties of Cu, Ni-doped Zn ferrites

Ferrite nanocomposites with the composition Cu0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4 were prepared by co-precipitation method. The effect of dopant to spinel ferrite ZnFe2O4 on the structural, morphological, optical, and dielectric properties of the as-prepared Cu-Zn and Ni-Zn ferrites were investigated. The structural, elemental, and optical properties conducted by using X-ray diffraction (XRD) technique with Cu/K alpha radiation, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Raman spectroscopy, and UV-Vis reflectance spectroscopy. For the electrical properties of the Cu-Zn and Ni-Zn ferrites, a real part of the dielectric constant and AC conductivity have been investigated with a frequency range of 20 Hz to 10 MHz at different temperature for each sample. The substitutions of Cu and Ni into the ZnFe2O4 nanocomposites crystal size calculated 20.36 nm for Cu-Zn ferrite and 10.95 nm for Ni-Zn ferrite. Also, the energy band gap of Cu-Zn ferrite is 2.6 eV and Ni-Zn ferrite is 2.83 eV. These results show that the energy band gap is increased when the crystal size is reduced by the substitution of Ni into the Zn ferrite. The dielectric constant and AC conductivity of Cu-Zn ferrite is bigger than the Ni-Zn ferrite at low frequencies. This situation is related to the structural parameters. Also, the AC conductivity increases with an increasing frequency and temperature.