Structural, electrical, and leakage-current characteristics of double perovskite: Sm2CoMnO6

Abstract

Double perovskite compound Sm2CoMnO6 was prepared by a high-temperature solid-state reaction route. The monoclinic structure of the compound was obtained by the X-ray structural analysis. The microstructure analysis reveals that there is an almost homogeneous distribution of grains with small voids. The detailed studies of dielectric and electrical properties, carried out in the frequency range of (1 kHz–1 MHz) at different temperatures (25–500 °C), have provided many interesting features of the material. The frequency dependence of dielectric parameters is described on the basis of Maxwell–Wagner model. In the study of temperature dependent dielectric parameters, an observed dielectric anomaly is considered as the ferroelectric-paraelectric phase transition. The complex impedance study (Nyquist plot) exhibits the existence of only grain effect which is represented by a single semicircle (RQC). The existence of the relaxation mechanism of the material is of non-Debye type that is established from the depression angle. In Nyquist plots both negative temperature coefficient of resistance (NTCR) and positive temperature of coefficient of resistance (PTCR) characteristics are observed in the compound. The frequency dependence of conductivity is analyzed by Jonscher’s power law which suggests that the existence of overlapping large polaron tunneling (OLPT) and correlated barrier hopping (CBH) conduction phenomena in the material. The temperature variation of leakage-current characteristics has been analyzed. The low leakage-current density is observed from the J–E characteristic curves.