Physical and electromagnetic properties of nanosized Gd substituted Mg–Mn ferrites by solution combustion method

Nanosized powders of Gd substituted Mg–Mn ferrites synthesized by solution combustion method using high purity metal nitrates are presented. These powders were calcined, compacted and sintered at 1250 °C. The powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The effect of Gd substitution on phase formation, microstructure and bulk density was also studied. Gd2O3 facilitates the formation of a secondary phase on the grain boundary which suppresses abnormal grain growth. The bulk density was found to decrease from 4.26 to 3.38 g/cm3 with an increase of Gd substitution, but the electrical resistivity was increased. Ferrite with a low dielectric constant in the range of 6–12 was observed and there was no maximum dielectric loss in the frequency range measured to 1 GHz. A decrease in saturation magnetization was also observed by a small fraction of Gd substitution. Correlation between magnetic properties and physical properties were discussed.