Effect of Sintering Temperature on Structure and Electric Performance of La0.67Ca0.33-xSrxMnO3 Ceramic

Double-doped La0.67Ca0.33-xSrxMnO3(x=0, 0.05, 0.15) powders were synthesized by traditional solid-state reaction method. Effects of sintering temperature on structure, micro morphology and metal-insulator phase transition temperature of La0.67Ca0.33-xSrxMnO3 ceramic were systemically studied. The results showed that sintering temperature had little influence on crystallinity or micro morphology of as-prepared ceramic, while double-doping effectively changed the phase transition temperature of the ceramics. When the ceramics sintered at 1400 degrees C the metal-insulator phase transition temperature increased from -20 degrees C to 6 degrees C and the ceramics stabilized in orthorhombic structure as the doping level varing from x=0 to x=0.05. At the doping level x=0.15, the crystal structure changed from rhombohedral to orthorhombic and the metal-insulator transition temperature was 17 degrees C. Under the same doping concentration, the metal-insulator phase transition temperature of the ceramics increased with the increase of sintering temperature. The above mentioned material may be an ideal candidate for active thermal control technology of long life satellites.