Synthesis of Sr- and Fe-doped LaGaO₃ perovskites by the modified citrate method

Abstract

Fine particle strontium and iron substituted lanthanum gallates La_1−x Sr _x Ga_1−y Fe _y O_3−δ, where x = 0.2, 0.4, and 0.6; y = 0.2, 0.4, 0.6, and 0.8, have been synthesized by a modified citrate method. The formation of these powders was confirmed by the X-ray powder diffraction (XRD) and the fine particle of La_0.6Sr_0.4Ga_0.2Fe_0.8O_3−δ was investigated by scanning electron microscopy (SEM), and particle size analysis. The single phase of La_0.8Sr_0.2Ga_0.4Fe_0.6O_3−δ, La_0.6Sr_0.4Ga_0.2Fe_0.8O_3−δ, and La_0.4Sr_0.6Ga_0.2Fe_0.8O_3−δ powders could be obtained both with and without calcination. The amount of the secondary phase increased when the amount of Sr in La_1−x Sr _x Fe_0.6Ga_0.4O_3−δ was more than 0.2 (x > 0.2) and the amount of Fe in La_0.6Sr_0.4Ga_1−y Fe _y O_3−δ and La_0.4Sr_0.6Ga_0.2Fe_0.8O_3−δ was less than 0.8 (y < 0.8). The results indicated that in the pH range of 1.36–9.27, the single phase of La_0.6Sr_0.4Ga_0.2Fe_0.8O_3−δ was formed without calcination and the pH had negligible effects on the structure and lattice parameter. The fine particle of these calcined powders (<4 μm) was obtained with the average particle size 1.70 μm at pH = 1.36 and with the average particle size between 0.56–0.60 μm at pH range between 3.39–9.27, and with a lattice parameter about 3.9 Å.