Dielectric behavior and ac electrical conductivity study of Sm 3+ substituted Mg–Zn ferrites

Abstract

Polycrystalline soft ferrites, Mg 1− x Zn x Fe 2− y Sm y O 4 ( x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0; y = 0, 0.05 and 0.10) was prepared by usual ceramic method. The single-phase spinel formation of ferrites was confirmed by X-ray diffraction technique. The dielectric measurements were carried out at room temperature as a function of frequency and composition. The experimental results reveal that dielectric constant and dielectric loss tangent decrease where as ac electrical conductivity increases as frequency increases. The ac electrical conductivity is derived from the dielectric measurements. The dielectric behavior is attributed to the Maxwell–Wagner type interfacial polarization. The conduction mechanism in these ferrites is due to electron hopping between Fe 2+ and Fe 3+ ions on adjacent octahedral sites. The composition dependence of ɛ′ and σ ac indicate that they increase with increase in Zn ion substitution and reach a maximum value and then they decrease. The addition of Sm 3+ content decreases the dielectric constant.