Influence of Nd super(3+) substitution on permeability spectrum of Zn-Mg ferrite

Polycrystalline ferrites, Zn sub(x)Mg sub(1-x)Fe sub(2-y)Nd sub(y)O sub(4) (x identical with 0.00, 0.20, 0.40, 0.60, 0.80 and 1.00; y identical with 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 Zn super(2+) concentration up to x identical with 0.40 and decreases thereafter, suggesting the existence of the canted spin. The compositions, for x greater than or equal to 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 delta , against frequency also shows dispersion. The variation of the loss factor tan delta / mu sub(i) against frequency exhibits resonating behaviour showing peak value at a critical frequency. The sharp resonance is observed for x identical with 0.00 and 0.60, whereas it becomes flat for x identical with 0.20 and 0.40. This suggests the suitability of the compositions for x identical with 0.20 and 0.40. On substitution of Nd super(3+) ion, the loss factor versus frequency curve is found to be suppressed, which results into widening the band of utility.