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Effect of temperature on electrical conductivity and dielectric properties for manganese substituted lithium ferrite

S.A.Mazen, N.I.Abu-Elsaad

Manganese substituted lithium-ferrite with the general formula Li0.5- 0.5xMnxFe2.5-0.5xO4 (where x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) were synthesized by the standard ceramic technique. The variation of dc and ac conductivities has been reported as a function of temperature from room temperature 293K up to 970K in static air.Ac measurements were carried out over a wide range of frequencies from100Hz up to 1MHz. The variation ln ó at room temperature with composition indicates that the conductivity initially increases up to 0.5 and then decreases with further addition in Mn content. The activation energy of conduction mechanism decreases from 0.68eV to 0.34eV. The electrical conduction in this ferrite is explained on the basis of the hopping mechanism. Dielectric properties such as dielectric loss tangent tan ä and dielectric constant åÂ’ have been measured. The dielectric behaviour is explained by using the mechanism of polarization process, which is correlated to that of exchange interaction.