Influence of Nd3+ substitution on permeability spectrum of Zn–Mg ferrite

Polycrystalline ferrites, ZnxMg1−xFe2−yNdyO4 (x=0.00, 0.20, 0.40, 0.60, 0.80 and 1.00; y=0.00, 0.05 and 0.10) were prepared by standard ceramic method. The magnetization study of the compositions show increase in saturation magnetization with Zn2+ concentration up to x=0.40 and decreases thereafter, suggesting the existence of the canted spin. The compositions, for x≥0.80 exhibit paramagnetic behaviour at and above room temperature. The frequency dependence of the initial permeability, permeability spectrum, was studied in the frequency range from 100 Hz to 1 MHz. This shows dispersion in permeability against frequency. The dispersion frequency is found to be lower for high permeability compositions than those of lower permeability. The graph of magnetic loss tan δ, against frequency also shows dispersion. The variation of the loss factor tan δ/μi against frequency exhibits resonating behaviour showing peak value at a critical frequency. The sharp resonance is observed for x=0.00 and 0.60, whereas it becomes flat for x=0.20 and 0.40. This suggests the suitability of the compositions for x=0.20 and 0.40. On substitution of Nd3+ ion, the loss factor versus frequency curve is found to be suppressed, which results into widening the band of utility.