Material properties of La0.8Sr0.2Ga0.9+xMg0.1O3−δ as a function of Ga content

The crystalline phases, sintering behavior, microstructure and conductivity of the compound La0.8Sr0.2Ga0.9+xMg0.1O3−δ (−0.02<x<0.04) were characterized as a function of Ga content. Depending on thermal treatment and Ga content, the compounds LaSrGa3O7, LaSrGaO4 and La2O3 were identified in addition to the perovskite phase. Dilatometric measurements have shown that a volume expansion occurs in the range from 1300°C to 1500°C, which decreases from x=−0.02 towards x=0.04. This seems to be due to the amount of the second phase LaSrGaO4 present. The ionic conductivity decreases with increasing Ga content, which is attributed to both the reduction of the oxygen vacancy concentration and the formation of the insulating LaSrGa3O7 phase.