Electrical and thermal properties of La0.7Sr0.3Ga0.6Fe0.4O3 ceramics

Single-phase La0.7Sr0.3Ga0.6Fe0.4O3 (LSGF) ceramic powder was prepared in one step at 1500 8C by solid-state reaction in air. The phase is a hexagonal (space group R-3c) at room temperature but becomes cubic at temperatures above approx. 600 8C. A high-density (97%) LSGF ceramic shows electrical conductivity of 4.3 S/cm (Ea = 0.32 eV) at 600 8C in air. The thermal expansion coefficient of LSGF changes drastically in air due to oxygen loss and phase transition. High-density LSGF ceramic is relatively stable in forming gas (8% H2, 92% Ar). However, the powder decomposes in forming gas above 700 8C with formation of LaSrGaO4. LSGF reacts with NiO at 1000 8C. The ability of LSGF to split the C\u8211H bond in methane at intermediate temperatures has been also evaluated.NRC publication: Ye