Study on the structure, DC electrical resistivity and magnetic properties of Co_0.7Cu_0.2Zn_0.1Fe_2-xCr_xO₄ nano ferrites

The sol-gel auto-combustion method synthesised Co_0.7Cu_0.2Zn_0.1Fe_2−𝑥Cr_𝑥O₄ (x = 0.0, 0.05, 0.1, 0.15, 0.2, and 0.25) nano ferrite materials. Analytical techniques were employed to study their structural, electrical, and magnetic properties. Powder X-ray diffraction techniques were used to investigate the structural properties and confirm the single-phase formation. The lattice constants, ranging from 8.451 to 8.336 Å, were consistent with reported values. The average crystallite sizes of the products, estimated using the Scherrer equation, fell between 42.25 and 31.25 nm. Microstructural analysis revealed the formation of nano-sized particles. The synthesized samples exhibited increased crystallite grains, with an average size ranging from 38.7 nm to 52.6 nm, and particles in the form of accumulating spheres were observed in FESEM investigations. FTIR spectra confirmed the formation of the spinel structure. The semiconducting nature of the ferrites was inferred from their electrical characteristics, such as their electrical resistance to direct current (DC). Room temperature magnetic properties, measured using a vibrating sample magnetometer, showed that saturation magnetization increased with the highest dopant concentration. Conversely, the coercive field values fluctuated as a function of Cr³⁺ doping. The size of crystallites, changes in the anisotropy constant, and cation distribution all impacted the coercivity behavior.