Dielectric properties of Mn-substituted Ni–Zn ferrites.

The dielectric properties of Mn[sub x]Ni[sub 0.5-x]Zn[sub 0.5]Fe[sub 2]O[sub 4] ferrites with x varying from 0.05 to 0.4 synthesized by the citrate precursor method have been investigated as a function of frequency, temperature, composition, and sintering temperature. An increase in the dielectric constant is observed with the increase in Mn concentration except for x = 0.3. Dispersion in the dielectric constant with frequency in the range of 100 Hz-1 MHz is observed. Resonance peaks were observed in tan δ[sub ∈] versus frequency curves for all samples. A shift in the resonance frequency towards higher frequency is observed with increase in temperature. The peak height also increases with increase in temperature. Possible mechanisms contributing to these processes have been discussed. From the temperature variation of the dielectric relaxation, activation energies for various samples have been calculated and compared with those obtained from dc resistivity. [ABSTRACT FROM AUTHOR]