Crystal structure and peculiarities of microwave parameters of Co_1-NiFe₂O₄ nano spinel ferrites

Nanosized spinel ferrites Co_1-NiFe₂O₄ (where x = 0.0-1.0) or CNFO have been produced using a chemical method. The crystal structure's characteristics have been determined through the utilization of X-ray diffraction (XRD). It has been demonstrated that all samples have a single phase with cubic syngony (space group Fd3̄m). The lattice parameter and unit cell volume behavior correlate well with the average ionic radii of Co²⁺ and Ni²⁺ ions and their coordination numbers. Thus, an increase in the Ni²⁺ content from x = 0.0 to x = 1.0 leads to a decrease in the lattice parameter (from 8.3805 to 8.3316 Å) and unit cell volume (from 58.86 to 57.83 ų). Elastic properties have been investigated using Fourier transform infrared (FTIR) analysis. The peculiarities of the microwave properties have been analyzed by the measured S-parameters in the range of 8-18 GHz. It was assumed that the energy losses due to reflection are a combination of electrical and magnetic losses due to polarization processes (dipole polarization) and magnetization reversal processes in the region of inter-resonant processes. A significant attenuation of the reflected wave energy (-10 … -21.8 dB) opens broad prospects for practical applications.