Properties and microstructural analysis of La1-xSrxGa1-yMgyO3-solid electrolyte ceramic

La(1-x)Sr(x)Ga(1-)yMg(y)O(3-delta) (x=0.1-0.2, y=0.1-0.2) (LSGM) electrolytes, which have high ionic conductivities, were synthesized by a solid-state reaction at 1500 degrees C. In our study, La0.9Sr0.1Ga0.9Mg0.1O3-delta and La0.9Sr0.1Ga0.8Mg0.2O3-delta crystallized in an orthorhombic (Imma) structure, and La1-xSrxGayMgyO3-delta (0.1 <= 0.2, 0.17 <= y <= 0.2) crystallized in a rhombohedral (R<(3)over bar>c) structure. Active Raman bands at approximately 532, 674, and 750 cm-I were observed in these samples because of the decrease in local symmetry induced by the oxygen vacancies. When x+y > 0.35, the conductivity was approximately 0.164-0.173 S/cm at 800 degrees C. The ionic conductivity mechanism changed at temperatures of approximately 500-650 degrees C. La0.9Sr0.1Ga0.9Mg0.1O3-delta and La0.9Sr0.1Ga0.8Mg0.2O3-delta samples possessed higher resistances at 300-400 C as a result of existing stacking faults and defects. The thermal expansion coefficients (TECs) were approximately 9.1 x 10(-6)/degrees C to 11 x 10(-6)/degrees C at 200-500 degrees C. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.