Magnetic and electrical properties of Mg1-xCoxFe2O4 (x = 0-0.15) ceramics prepared by the solid-state method

TLDR: In this paper, the microstructure revealed that the grain size and density increased upon cobalt doping due to the higher ionic mobility of cobalt than magnesium ions, and the dielectric behavior was explained based on the Maxwell-Wagner two-layer model.

Abstract: Mg1-xCoxFe2O4 (x = 0−0.15) ferrite powders were synthesized by the solid-state reaction followed by a liquid phase sintering at 1050 °C using 3 wt% Bi2O3 as a sintering aid. The grain size and density increased upon cobalt doping due to the higher ionic mobility of cobalt than magnesium ions. The microstructure revealed that, upon cobalt doping, the average grain size increased from 2.43 ± 1.52–3.59 ± 2.05 μm. The highest density of 4.52 ± 20 g/cm3 was obtained for x = 0.11. The saturation magnetizations of the samples progressively increased from 23 to 52 emu/g by increasing the cobalt content. The DC resistivity increased up to 6.45 × 10+10 Ω.cm for x = 0.11. The dielectric behavior was explained based on the Maxwell-Wagner two-layer model. The samples with x = 0; 0.03; 0.07; and 0.15 showed a high-lossy behavior, whereas with x = 0.11 exhibited a low tanδ of 0.048 and the dielectric constant of 16.8 at 1 kHz.