Study of charge transport mechanism in Ba doped Sr2CrMoO6 double perovskite mixed ionic electronic conductor

Abstract

In this work, the conduction mechanism in B a x S r 2 − x CrMo O 6 (0 ≤ x ≤ 0.3) double perovskite has been investigated using different techniques, such as universal dynamic response (UDR) and modulus spectroscopy. AC impedance spectroscopy has been studied in the frequency range of 0.3 Hz–5 MHz in a wide range of temperatures. It has been found that the conduction mechanism is thermally activated and frequency-dependent. The impedance fitting response to the microstructure reveals that grain boundaries are more resistive and capacitive than grains. Analysis of the complex modulus indicates that both short- and long-range charge carrier transport is responsible for conduction with non-Debye-type response in these oxides. The permittivity analysis indicates the existence of both universalities, near constant loss and UDR. Furthermore, from the Almond West power law, hopping frequency ( ω c) and activation energy E a c have been calculated. The relaxation time and DC conductivity are found to obey Barton Nakajima and Namikawa's relation. In addition, the Kramers–Kronig relation and conductivity scaling are discussed to validate the impedance data and provide insight into the conduction processes in this mixed ionic electronic conductor.