Controlling the properties of Mn-Zn ferrites at high frequency by substituting In³⁺ and Al³⁺ ions

42-46The effect of substitution of In³⁺ and Al³⁺ ions on the electrical and magnetic properties of Mn-Zn spinel ferrites has been investigated. The substitution of In³⁺ ions in place of Fe³⁺ions resulted in an increase of lattice parameter, because of the larger size of the substituted ions, whereas lattice pa-rameter decreased on substituting Al³⁺ ions in place of the Fe³⁺ ions, owing to their smaller size. The dc resistivity was found to increase with the substitution of In³⁺ and Al³⁺ions in the Mn-Zn ferrite system. The improvement in the dc resistivity has been observed at the expense of deterioration in the magnetic properties of Al³⁺ substituted Mn-Zn Ferrites. A significant reduction in the value of initial permeability, saturation magnetization and Curie temperature was observed with successive increase of Al³⁺ions. The saturation magnetization and initial permeability were found to increase with incor-poration of In³⁺ ions. A marked increase in the value of initial permeability was found for the Mn₀․₄Zn₀․₆In₀․₅Fe₁․₅O₄ ferrites. The Curie temperature was found to decrease with an increase of In³⁺ ion concentration. Possible mechanisms contributing to these processes have been discussed