Structure, charge carrier conduction, dielectric properties and leakage current density of Dy2CoMnO6 double perovskite

Abstract

In this study, the structure, charge transport properties, dielectric properties, and leakage current density of Dy2CoMnO6 double perovskite are investigated. The sample is prepared via auto–ignition method. The Rietveld refinement of the X–Ray diffraction pattern of the sintered sample reveals the monoclinic phase with space group P21/n. The crystal structure of the sample is distorted and tilted. The dominant oxidation state of Co and Mn are +3 and +4, which are estimated from the bond valence sum method. The values of activation energy for dc conduction are 0.16 eV (≤ 75 ℃) and 0.37 eV (≥ 100 ℃). The charge carrier conduction follows a correlated barrier hopping mechanism (≤ 75 ℃). Scaling spectra confirms the temperature independence nature of the conduction and relaxation mechanism below 75 ℃. The grain boundary conductivity is higher than the grain interior conductivity due to the low grain boundary blocking factor. The sample exhibits a non–Debye type nature. The value of the tangent of dielectric loss lies from 4.15 to 33.11 in the frequency range from 50 Hz to 500 KHz, and the value of real part of complex dielectric constant lies between 102 and 67608 in the frequency range from 500 Hz to 50 kHz. The analysis of the imaginary part of the complex dielectric constant confirms the predomination of the dc electrical conduction process in the sample. The comparable values of the activation energy for dc conduction, grain interior conductivity, grain boundary conductivity, migration energy, and activation energy confirm the interlinking among these processes. The room temperature leakage current density is 4.36 × 10–4 Acm–2 at 8.05 Vcm–1. The leakage current density follows the Ohmic conduction and has been explained with the Schottky barrier model.