Structure, optical, charge transport mechanism, dielectric properties and leakage current analysis of Sm2MgMnO6 double perovskite

Abstract

Structure, optical, dielectric, charge transport properties, and leakage current density of Sm2MgMnO6 prepared via auto–combustion method have been investigated in this study. The stoichiometry of the constituent elements in the prepared sample agrees with the expected values. The sintered sample exhibits a monoclinic crystal structure with space group P21/n. The crystal structure is distorted and tilted. The grains are irregular in shape and size and distributed non–uniformly. The average crystallite and grain size are 151 nm and 176.49 nm, respectively. The direct optical band gap (1.41 eV) is associated with octahedral distortion. The tangent of dielectric loss increases beyond ∼300 °C rapidly. The Havriliak–Negami formalism has been used to explain the dielectric properties. The material is relaxor ferroelectric in nature. The conduction of charge carriers follows non–overlapping small polaron tunneling (NSPT) conduction model. The ac activation energy decreases with frequency. The leakage current conduction is Ohmic in nature. The sample exhibits 1.53 × 10−6 Acm−2 leakage current density at 5.11 Vcm−1 and 150 °C, which follows the Schottky emission relation. The obtained results have been compared with the literature.