Copper ferrite CuFe2O4 nanoparticles were synthesized by sol-gel method with different annealing temperatures (200, 450, 650 and 850) °C. Structural, morphological, magnetic and electrical properties were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM) and LCR meter. The XRD patterns showed the system structure in Cu-ferrite had deformed at 650 °C from a cubic to a tetragonal system with apparrent a secondary phase CuO. Lattice constant decreases with increasing annealing temperatures, while crystalline volume increases. The FT-IR spectrum of sample under investigations shows two significant absorption bands, which refer to the formation of a single-phase cubic spinel. Magnetization revealed a soft ferromagnetic behavior for the composition sintered at 850 °C. The saturation magnetization, remnant magnetization, and coercivity were 32 emu.g−1, 11.64 emu.g−1, 517.16 emu.g−1, respectively. The electrical measurement of sample shows decrease in the real and imaginary part of dielectric constant with increasing frequency while and AC conductivity increasing.

Citrate-gel auto combustion technique was used to synthesize nickel-copper mixed ferrite nanoparticles NixCu1-xFe2O4 (x= 0.0, 0.4, 1.0) with different calcinating temperatures (200, 450, 650 and 850 °C). Structural, morphological, magnetic, and electrical properties were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and LCR meter in order to determine significant influences of Cu2+ cations content in nickel ferrite. The XRD patterns showed that all compositions had cubic spinels, except CuFe2O4 samples. The system structure in Cu-ferrite was deformed at 650 °C  from a cubic to a tetragonal system with a secondary phase CuO. Lattice constant was decreased with increasing Cu2+ cations substitution in Ni-ferrites, while crystalline volume was increased. With the help of Debye-Scherrer`s equation using XRD data, we found that the crystallite size at 850 °C is lying in the range from 38.70  to 48.00 nm. The FTIR spectrum of samples under investigation showed two significant absorption bands, which refer to the formation of a single-phase cubic spinel. The magnetization test revealed a soft ferromagnetic behavior for all the compositions sintered at 850 °C. The saturation magnetization (Ms) was decreased with the substitution by Cu2+ cations, while remnant magnetization (Mr) and coercivity (Hc) were increased in Cu-ferrite. The highest Ms value was 42.25 emu.g-1 for Ni-ferrite, while the highest Hc value was 517.16 Oe for Cu-ferrite. The electrical measurement of samples showed an increase in the real dielectric constant and AC conductivity at a frequency range of 20Hz-3MHz with the addition of copper cations.