Significant Promotion to Electrical Properties of Sm Modified BaLa _x Sm _x TiO₃ (0.001 ≤ x ≤ 0.005) Powders: A Novel Precursor Gaseous Penetration Route

Novel modification route of precursor gaseous penetration was applied to promote the electrical properties of Sm modified La and Sm co-doped BaTiO₃ powders. Variations in structure, constitution, morphology, and electrical properties were investigated. The study revealed that co-doping of La and Sm each 0.3 at% decreased the resistivity of BaTiO₃ powders to the minimal point of 6.41 × 10⁶ Ω·m, and the lower point of 1.74 × 10³ Ω·m was obtained by conventional gaseous penetration of Sm, however, the precursor gaseous penetration significantly declined the resistivity to lowest point of 6.27 Ω·m. The co-doping of La and Sm increased the dielectric constant and decreased the loss tangent of BaTiO₃ powders, and extra high dielectric parameters were observed which was caused by percolation. Especially, the intensive tendency of metallization of BaTiO₃ powders which originated from the synergistic effects during precursor gaseous penetration induced the anomalous impedance response and the complexity of resistivity-temperature response. The XRD and SEM analyses illustrated that complex reactions at grain boundary region were occurred after gaseous penetration of Sm and new compounds of Sm, SmO, and BaSmO₄ were generated. Moreover, precursor gaseous penetration intensively enhanced those reactions and extra compounds of SmTiO₃Cl was identified. Respectable heterogeneous appearances on the surface of modified BaTiO₃ powders were considered to be caused by the novel precursor gaseous penetration route.