Structural, dielectric, electrical and magnetic properties of CuFe₂O₄ nanoparticles synthesized by honey mediated sol–gel combustion method and annealing effect

In this work, CuFe₂O₄ nanoparticles were synthesized by natural source of glucose and fructose (i.e., honey)—mediated sol–gel auto-combustion method. Grain size, cation distribution and crystal phase were further tuned through annealing at higher temperature 500, 700, 900 and 1100 °C. The structural investigation was performed using powder X-ray Diffraction, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and X-ray Photoelectron Spectroscopy. X-ray diffraction study confirmed the phase transformation from cubic to tetragonal as a function of annealing temperature. Magnetic properties were investigated by using vibrating sample magnetometer under an applied magnetic field of 10 kOe at room temperature. The highest value of saturation magnetization (M_s) was 26 emu/g for ferrite nanoparticles annealed at 1100 °C, whereas the lowest value was 11 emu/g for annealed at 700 °C. The highest and lowest coercivity (H_c) was 1389 and 65 Oe for ferrite nanoparticles annealed at 900 and 1100 °C, respectively. Detailed study of modulus and impedance spectroscopy revealed the contribution of grain and grain boundary on electrical transport mechanism and relaxation process. Further, dependence of relaxation time, resistance and capacitance at grain and grain boundary on grain size, cation distribution and annealing temperature was noticed. The asymmetry of peak in imaginary part of modulus spectra indicates that the relaxation process is non-Debye type. At lower frequency, ac conductivity is frequency independent, whereas, at high frequency, it follows an apparent power law, σ(ω) α ω^s. Dielectric parameters (real and imaginary part, dielectric loss) with variation of frequency (1 Hz to 10 MHz) are investigated and dependence with frequency and annealing temperature is observed.