Structural, Magnetic, and Dielectric Properties for Mg0.6Co0.2Cu0.2FeCrO4 Spinel Ferrites Prepared Under Different Calcination Temperatures

The calcination temperature effects on structural, magnetic, morphological, electrical, and dielectric properties for Mg_0.6Co_0.2Cu_0.2FeCrO₄ spinel ferrites have been investigated in this work. The samples (abbreviated as S900 and S1100) were prepared by the sol-gel route and calcined at two different temperatures (900?°C and 1100?°C). The thermogravimetric analysis was used to investigate the weight loss versus temperature and the formation of the spinel phases. The cation distributions were estimated for the samples using experimental XRD patterns based on the Rietveld refinement of the atomic occupancy values. With increasing calcination temperature, unit cell parameters and average crystallite size show an increasing trend. From the magnetic hysteresis loops, low coercive fields were obtained, making Mg_0.6Co_0.2Cu_0.2FeCrO₄ ferrites suitable candidates for soft magnetic devices. Nyquist-diagrams modeling shows that the conduction process in the samples is governed by the effect of grain and grain boundary contributions. Impedance and modulus curves show a dielectric relaxation phenomenon in the samples with non-Debye nature. The samples show electrical insulating (I)-semiconducting (S) transitions at T_IS?=?360?K for S900 and T_IS?=?400?K for S1100. Both NSPT and CBH models were used to explain the sample conduction process. Due to the increase in crystallite size with increasing calcination temperatures, activation energies decrease from 0.279 to 0.211?eV for S900 and S1100, respectively. In addition, the synthesized materials exhibit low dielectric constants and dielectric losses at higher frequencies as well as high electrical resistivity. These properties make Mg_0.6Co_0.2Cu_0.2FeCrO₄ samples suitable candidates for high-frequency applications and microwave absorption devices.