Dielectric and Magnetic Properties of Co$_{2}$O$_{3}$ Modified 0.4PZT${+}$0.6NiCuZn-Ferrite Composites

In order to improve the electromagnetic properties of 0.4PZT${+}$0.6NiCuZn-ferrite composites for suppressing electromagnetic interference (EMI), Co$_{2}$O $_{3}$ was introduced. The effects of Co$_{2}$O$_{3}$ content on the electromagnetic properties of the composite materials were investigated. It was confirmed the existence of local induced anisotropy caused by ordering of Co$^{2 +}$ ions. Permeability spectra of the composites with different Co $_{2}$O $_{3}$ content had been resolved into contributions of domain wall resonance and spin rotation relaxation. The fitting results of permeability dispersion revealed the relationships among domain wall resonance, spin rotation relaxation mechanisms, and local induced anisotropy. This increase in local inducted anisotropy results in a decrease of initial permeability and an increase of Q-factor. Meanwhile, Co $_{2}$O $_{3}$ additive can improve the dielectric constant and the loss tangent (tan$\delta$ e) by increasing the oxygen vacancy concentration.