Structure and electrical conductivity properties of K doped Sr_1−xK_x(Sr_0.50Nb_0.50)O_2.75−δ complex perovskites

Abstract

In the present study structural and electrical conductivity properties of complex perovskites with general formula Sr 1−x K x (Sr 0.50 Nb 0.50 )O 2.75−δ have been studied. Potassium is doped in the cuboctahedral Sr site Sr 1−x K x (Sr 0.50 Nb 0.50 )O 2.75−δ with different dopant concentrations such as x=0, 0.25, 0.50, 0.75 and 1. The structural and morphological properties of Sr 1−x K x (Sr 0.50 Nb 0.50 )O 2.75−δ were studied using Thermogravimetry (TG) analysis, x-ray diffraction (XRD) and Scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was performed to investigate the electrical properties. The effect of structural and morphological variations associated with the dopant concentration affecting the electrical conductivity behaviour of Sr 1−x K x (Sr 0.50 Nb 0.50 )O 2.75−δ complex perovskite oxides were studied in detail. The higher total conductivity was observed for 100% K doped (x=1, 3.10×10 −5 S cm −1 at 800°C) and 25% K doped (x=0.25, 2.02×10 −5 S cm −1 at 800°C) composition.