Electrical Properties of Cobalt Substituted NZCF and ZNCF Nanoparticles Prepared by the Soft Synthesis Method

Abstract

The soft chemical method was adopted for the synthesis of cobalt substituted nickel-zinc and zinc-nickel ferrites (Ni_0.95-xZn_0.05Co_xFe₂O₄ and Zn_0.95-xNi_0.05Co_xFe₂O₄ for x= 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06. We have recently studied the structural, morphological, magnetic properties, initial permeability, and dielectric constant of the samples. They are found with cubic ferromagnetic spinel structure along with the morphology suitable for high-density recording media. The effective initial permeability μi (μ_eff) is found to depend on magnetocrystalline anisotropy constant K₁ and grain size D. From this present study, the dc resistivity is found to increase linearly with Co²⁺ substitution for both ZNCF and NZCF ferrites up to x=0.04. After that, the material changes its ferromagnetism to paramagnetism thereby increasing the activation energy. The difference between the two magnetic states (Ferro and para) in NZCF is found to be greater than in ZNCF. The phase transition helps to determine the Curie temperature. The ac conductivity takes place by the hopping of charge carriers called polarons. The conductivity is enhanced with frequency.