Cd-substituted NiZnCo ferrite with high dielectric constant and low coercivity for high-frequency electronic devices

This work investigated the effect of replacing Zn²⁺ ions with Cd²⁺ ions on the microstructure and electromagnetic properties of NiZnCo ferrites. The studies show that the Cd²⁺ ions substituted for Zn²⁺ ions at the A sites (tetrahedral sites) of the ferrite lattice. The large ionic radius of the Cd²⁺ ions can cause lattice distortion. Concurrently, the low melting point of CdO can effectively reduce the sintering temperature of NiZnCo ferrite, thereby significantly changing the magnetoelectric properties of NiZnCo ferrite. These changes are mainly manifested as the decrease in the saturation magnetization (Ms) from 66.6 to 58.5 emu/g and the increase in coercivity (Hc) from 31.2 to 34.8 Oe. The dielectric constant increases considerably, dielectric loss tanδ gradually decreases from 4.71 to 0.83 at 10 kHz, and DC resistivity ρ decreases considerably from 8.0 × 10⁴ to 1.61 × 10⁴ Ω m. Therefore, the substitution of Cd²⁺ ions in NiZnCo ferrite provides excellent electrical and magnetic properties, which provide a reference for the development of high-frequency miniaturized electronic equipment.