Frequency dependence of electrical and magnetic properties of Li–Ni–Mn–Co ferrites

Substituted Li-ferrites with compositional formula Li0.45−x/2Ni0.1Mn0.1CoxFe2.35−x/2O4 with xx ranging from 0 to 0.1 in steps of 0.02 were prepared by the conventional ceramic technique. The single-phase spinel structure of the samples was confirmed by XRD analysis. The lattice constant was observed to increase with the increase of the Co2+ substitution. The dielectric constant, ε′ε′ and dielectric loss tangent, tan δδ was studied as a function of frequency in the range 100 Hz to 1 MHz. A decrease is observed in the value of ε′ε′ with substitution at lower frequencies. ε′ε′ showed a dispersive behavior with frequency for all the samples. The frequency dependence of tan δδ showed a resonance peak. The magnetic properties viz initial permeability and magnetic loss were also studied as a function of frequency. The possible mechanisms contributing to the results have been discussed.

► The influence of Co2+ substitution on some properties of Li–Ni–Mn ferrites is studied. ► Co2+ significantly influences the structural properties even with small substitutions. ► The frequency dependence dielectric constant showed dispersion at low frequency. ► Maximum of tanδtanδ is significantly influenced by Co2+ content. ► Frequency dependence of permeability showed operational limit ∼2–5 MHz.