To study the structural, electrical, and magnetic properties of M (M = Mg2+, Mn2+, and Cd2+) doped Cu-Ni-Co-La spinel ferrites.

Tertiary Cu 0.25 Ni 0.15 M 0.25 Co 0.35 La 0.15 Fe 1.85 O 4 (M = Mg 2+ , Mn 2+ , and Cd 2+ ) spinel ferrites powders were prepared using the cost-effective sol-gel auto combustion route. The lattice parameters, absorption and vibrational bands, energy band gap, AC conductivity, and dielectric loss of the as-prepared ferrites were all measured. The Cd2+ doped ferrite has a minimum crystallite size (D) of 50.9 nm, which is smaller compared to Mg2+ and Mn2+ doped ferrites. Furthermore, the X-ray diffraction (XRD), as well as Fourier transform infrared radiation (FTIR) and Raman analysis confirmed the doping of Mg2+, Mn2+, and Cd2+ ions on their respective lattice sites. The resistivity of the divalent ions (Mg2+, Mn2+, and Cd2+) doped ferrites decreased in the para region and increased in the ferro region as the temperature increased. Moreover, the resistivity of the Cd2+ doped ferrite was smaller when compared to the ferrites doped with Mg2+ and Mn2+ ions. From Arrhenius plots, the minimum activation energy (Δ E) 0.8671 eV was observed for Cd2+ doped ferrites. The Cd2+ substituted ferrite also has the smallest AC conductivity and dielectric loss compared to Mg2+ and Mn2+ substituted ferrites. The coercivity and saturation magnetization were 136.41 Oe and 92.29 emu/g for the Cd2+ doped ferrite, respectively. These results suggest that the Cd2+ doped ferrite material could be used in high-frequency and high-power applications. • The Cu 0.25 Ni 0.15 M 0.25 Co 0.35 La 0.15 Fe 1.85 O 4 (M = Mg 2+ , Mn 2+ , and Cd 2+ ) spinel ferrites were prepared. • Minimum activation energy and maximum optical bandgap energy were observed for Cd-CNCL ferrite. • The minimum coercivity and maximum initial permeability were found for Cd-doped CNCL ferrite. • The Cd2+ doped CNCL ferrite exhibits minimum dielectric losses. • The Cd2+ doped CNCL ferrite is best for high-frequency and high-power applications. [ABSTRACT FROM AUTHOR]