Studies on electrical properties of La0.8Sr0.2Ga0.8Mg0.2O2.80 (LSGM) and LSGM-SrSn1−xFexO3 (x = 0.8; 0.9) composites and their chemical reactivity

We report the electrical conductivity properties of solid-state synthesized perovskite-like La0.8Sr0.2Ga0.8Mg0.2O2.80 (LSGM) and LSGM-SrSn1−xFexO3 (x = 0.8; 0.9) composites. LSGM exhibits both bulk and grain-boundary contribution in the ac impedance plots. The grain-boundary conductivity (σgb) is slightly (≤half-order of magnitude) higher than that of the bulk oxide ion conductivity (σbulk). Powder XRD study reveals that no chemical reaction occurs between LSGM and SrSn1−xFexO3 (1:1 wt.%) at 1000 °C (48 h) and forms a single-phase perovskite-like compound at 1300 °C (48 h) in air, while in hydrogen atmosphere, at 800 °C for 48 h, a growth of LaSrGaO4 and LaSrGa3O7 impurity phases and formation of metallic Fe was observed. The LSGM-SrSn1−xFexO3 (x = 0.8; 0.9) composites show a single or part of semicircle in air at low-temperature regime. The electrical conductivity of the composites were found to be much higher compared to pure LSGM and lower about an order of magnitude than those of pure Sn-doped SrFeO3 perovskite.