Redistribution of cations and enhancement in magnetic properties of sol–gel synthesized Cu_0.7−x Co _x Zn_0.3Fe₂O₄ (0 ≤ x ≤ 0.5)

Cu_{0.7− x} Co _x Zn_0.3Fe₂O₄ (0 ≤ x ≤ 0.5) nanoparticles are prepared by sol–gel auto combustion method, using copper nitrate, zinc nitrate, ferric nitrate, cobalt nitrate, and citric acid as the starting materials. The process takes only a few minutes to obtain as-received Co-substituted Cu–Zn ferrite powders. X-ray diffraction (XRD), vibrational sample magnetometer and thermo gravimetric analysis are utilized in order to study the effect of variation in the Co substitution and its impact on particle size, lattice constant, density, cation distribution and magnetic properties like magnetization, coercivity, remanent magnetization, ferritization temperature and associated water content. Lattice parameter found to increase with increasing Co content, whereas X-ray density, bulk density, particle size showed decreasing trend with the Co content. Cation distribution indicates that the Co and Cu ion show preference towards octahedral [B] site, Zn occupy tetrahedral (A) site whereas Fe occupy both tetrahedral (A) and octahedral [B] site. Redistribution of cations takes place for x > 0.3. Saturation magnetization (Ms) increases from 52.99 to 79.62 emu/g (x ≤ 0.3), for x > 0.3 Ms decreases with increase in Co content x. However, coercivity, magnetocrystalline anisotropy and remanent magnetization increases with the Co²⁺ substitution.