Synthesis and characterization of rare-earth ion-based double perovskite: Gd₂CoMnO₆

Abstract

The double perovskite gadolinium cobalt manganate (Gd₂CoMnO₆) ceramic material was prepared via mixed oxide route. The preliminary X-ray structural study reveals that the material was found in monoclinic structure. We have found the small voids with almost uniform distribution of grains from the microstructural analysis. Analysis of the dielectric and electrical data, collected in a wide range of frequency range (1 kHz–1 MHz) and temperature (25–500 °C), has provided many interesting results. We have discussed frequency dependence dielectric parameter by Maxwell–Wagner model. We found that the room temperature dielectric constant at 1 kHz frequency is 300 and tangent loss is nearly equal to 2. A dielectric anomaly (ferroelectric–paraelectric phase transition) was found in the temperature dependence of dielectric study. The study of diffuse phase transition exhibits the existence of relaxation process in the compound. In the Nyquist plots, both grain and grain boundary effects are observed which is characterized by (RQC) and (RQC)(RC) circuits. As the resistance decreases with increase of temperature, the material shows the semiconductor behavior. The existence of non-Debye type of relaxation mechanism in the material is confirmed by the depression angle. The frequency dependence of electric conductivity has been studied using the Jonscher’s power law, in which the frequency exponent n (< 1) signifies the translational motion with involvement of an intuitive hopping of charge carriers. The leakage current and conduction mechanism follow the space charge-limited conduction phenomenon. The low leakage current density may be suitable for high-temperature applications.