Study of the Electrical and Magnetic Properties of MnZn Ferrite by Equivalent Electrical Elements

This paper investigates the electrical and magnetic properties of Cobalt-substituted Manganese-Zinc soft ferrite by the equivalent lumped elements acquired from the appropriate equivalent electrical circuit of poly crystalline ferrite. The equivalent lumped circuit, combined with equivalent lumped resistances and capacitance, is applied to investigate the effect of microstructure on electrical and magnetic properties of Cobalt-substituted Manganese-Zinc ferrites. Replacing a small portion of Fe²⁺ with Co²⁺ remarkably increases the bulk resistivity of the MnZn ferrite and decreases the core loss with lower eddy current loss. A longer isothermal duration causes grain growth and forms a larger equivalent capacitance, which conducts a drop of hysteresis loss. However, excess substitution of Co²⁺ for Fe²⁺ is disadvantageous to magnetic permeability and raises core loss. The DC resistivity and magnetic permeability were measured by impedance analyzer at room temperature. The total loss of Mn_0.58 Zn₀₃₇Co_0.01Fe_2.04O₄ ferrite core does not exceed 420 m W/cm³ at 300 kHz/70 mT.