Material properties of La0.8Sr0.2Ga9+xMg0.1O3-delta as a function of Ga content

The crystalline phases, sintering behavior, microstructure and conductivity of the compound La0.8Sr0.2Ga0.9-xMg0.1O3-delta (-0.02<x<0.04) were charact erized as a function of Ga content. Depending on thermal treatment and Ga c ontent, the compounds LaSrGa3O7, LaSrGaO4 and La2O3 were identified in addi tion to the perovskite phase. Dilatometric measurements have shown that a v olume expansion occurs in the range from 1300 degreesC to 1500 degreesC, wh ich decreases from x=-0.02 towards x=0.04. This seems to be due to the amou nt of the second phase LaSrGaO4 present. The ionic conductivity decreases w ith increasing Ga content, which is attributed to both the reduction of the oxygen vacancy concentration and the formation of the insulating LaSrGa3O7 phase. (C) 2000 Elsevier Science B.V. All rights reserved.