Synthesis and characterization of Sr- and Mg-doped LaGaO 3 by using glycine–nitrate combustion method

Abstract

The Sr- and Mg-doped LaGaO 3 powders with the composition of La 0.85Sr 0.15Ga 0.85Mg 0.15O 2.85 were synthesized by using glycine–nitrate combustion method. The results show that unsintered powders prepared by glycine–nitrate combustion method contain the main phase (LaGaO 3). The samples contain less amount of secondary phases than by the sol–gel method and solid-state reaction method at the same sintering temperature. It will help to obtain LSGM materials with high conductivities .The sizes of synthesized powders are greater than those by the sol–gel method and smaller than those by solid-state reaction method. The sintering shrinkage analysis shows that the sintering temperature of LSGM prepared by glycine–nitrate combustion method is about 1432 °C, at least 60 °C lower than that by solid-state reaction method. The ionic conductivity increases with the increase of testing temperature. The curve of ln( σT) versus 1/ T exists two straight lines. This shows that activation energy of oxygen-vacancy motion at lower temperatures is greater than that at higher temperatures.