Study of electrical transport properties of Eu~+Substituted MnZn-ferrites synthesized by co-precipitation technique

摘要

Eu substituted MnZn-ferrites with nominal composition Mn_(o.78)Zn_(o.22)Eu_xFe_(2_X)O_4 (x=0.0, 0.02, 0.04, 0.06, 0.08 and 0.10) were prepared by co-precipitation technique. The effect of Europium substitution on electrical transport properties of Mn-Zn ferrites is reported. XRD analysis reveals fee phase in all the samples along with few traces of second phase. The lattice constant shows decreasing trend with the substitution of Eu due to partial solubility of Eu-ions in the lattice. Room temperature resistivity both at 10 and 20 V shows on average an increasing trend. This increase in resistivity is attributed to the unavailability of Fe~(+3) ions in the lattice due to Eu-substitution. The dc resistivity decreases with temperature for all the samples at 10 V and 20 V indicating the semiconducting behavior of these samples. Room temperature dc resistivity and activation energies show similar trend both at 10 V and 20 V indicating that the samples with high resistivity have high activation energies and vice versa. The dielectric constant (ε')> complex dielectric constant (e") and loss tangent of these samples decreased with the increase of Eu-concentration, following the Maxwell-Weigner model.