Sol-Gel Synthesis and Phase Evolution of ABO3 Oxide Compounds with A = La, Y, Lu and B = Al, Ga, Sc, In

Twelve nominal ABO3 compositions, where A = La, Y, Lu and B = Al, Ga, Sc, In, were synthesized by the sol-gel method and annealed at 700–1300 °C. The phase formation behavior was evaluated using tolerance factor calculations, XRD, Rietveld refinement, FTIR, SEM, SEM-EDX, and ICP-OES analysis. La-based compounds showed the highest tendency to form perovskite phases, while Y-based samples revealed strongest phase competition, and Lu-based materials mainly formed non-perovskite structures. LuScO3 and LuInO3 have a cubic bixbyite-type structure, whereas LuAlO3 and LuGaO3 formed garnet and Lu2O3 oxide-containing mixtures. The FTIR results confirmed the formation of metal–oxygen bonds during annealing, while SEM revealed agglomerated and porous powders with composition-dependent differences in apparent morphological feature size. SEM-EDX mapping revealed homogeneous elemental distributions, while ICP-OES confirmed that the A/B cation ratios remained close to the nominal ABO3 stoichiometry, suggesting that the secondary phase formation was mainly related to phase stability rather than deviation in composition.