Study of the structural, magnetic and electrical properties of Gd-substituted Mn–Zn mixed ferrites

The effect Gd3+ ion substituted for iron in Mn–Zn ferrites with formula of Mn0.55Zn0.45GdxFe2−xO4, where x = 0, 0.01, 0.03, 0.05 and 0.08, were prepared by double sintering ceramic technique. Microstructural and phase analyses were carried out using a scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. Formation of ferrites has also been studied by using FTIR. The lattice parameter was found to increase with increasing Gd-content which follows Vegard’s law. Curie temperatures (Tc) determined from the temperature dependence of initial permeability (μ′) were found to decrease with the increase of Gd-content due to weakening A–B exchange interaction. The magnetic properties of the samples were characterized by impedance analyzer and vibrating sample magnetometer (VSM). The dc resistivity has been studied as a function of temperature. The resistivity was found to increase in the order of ∼107 Ω-cm for Gd-substituted samples probably due to the formation of a non-conducting layer in the grain boundary. The activation energy in paramagnetic region was higher than that of ferromagnetic. The observed dielectric properties were explained on the basis of electron conduction mechanism.

► Characterized Gd-substituted Mn–Zn mixed ferrites.
► Phase formation was explored in details.
► The grain growth is stemmed due to increase Gd-content.
► Saturation magnetization decreases with Gd-content.
► Substantial enhancement of resistivity due to Gd-substitution.