PREPARATION OF LA1-XSRXMNO3 (0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.6) POWDER BY AUTOIGNITION OF CARBOXYLATE-NITRATE GELS

Fine powders of Sr-substituted LaMnO3 have been prepared at relatively low temperatures by autoignition of citrate-acetate-nitrate gels. The ignition temperature and the enthalpy change during the combustion vary with strontium content leading to a variation of average particle size in the range 0.3 to 3 mum. As-ignited powders, particularly with less strontium substitution, are amorphous in nature. However, the crystallographic phase becomes either pseudocubic or rhombohedral or orthorhombic depending on the calcination temperature as well as the extent of substitution.