Synthesis and Characterization of Barium Lanthanum Titanates

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Abstract
Ternary compounds in the system BaO—TiO2—La2O3 were prepared by the solid‐state reaction technique at temperatures between 1300° and 1400°C using precursor oxides as the starting materials. In an alternative processing technique, BaTiO3 was reacted with appropriate proportions of prefabricated lanthanum titanates at 1350°C to obtain the compounds. Two compounds were identified in the TiO2‐rich region of the system. The X‐ray powder diffraction pattern of a compound with a chemical composition BaLa2Ti3O10 (BaO·La2O3·3TiO2) is indexed on the basis of an orthorhombic unit cell with a= 7.665 × 10−1 nm, b= 28.524 × 10−1 nm, and c= 3.876 × 10−1 nm. The other compound, which has a chemical composition Ba4La8Ti17O50 (BaO·La2O3·4.25TiO2) occurs in a narrow homogeneity range within the system. The X‐ray powder diffraction pattern of the compound is indexed on the basis of an orthorhombic unit cell with a= 12.317 × 10−1 nm, b= 22.394 × 10−1 nm, and c= 3.881 × 10−1 nm. Both the compounds are compatible with BaTiO3 and form pseudobinary joins with BaTiO3 in the system BaO—TiO2—La2O3.