Synthesis, structure, and dielectric properties of a novel perovskite-based nanopowders via sol–gel method: (1–x)BaTiO₃–xDyScO₃

A sol–gel method was adopted to synthesize novel perovskite-based nanopowders: (1–x)BaTiO₃–xDyScO₃ (0 ≤ x ≤ 0.06), which exhibited a relatively pure pseudo-cubic perovskite structure when xerogel was calcined at 750 °C. Through the employment of PEG 400 as dispersant, narrow size distributed particles of ~15–20 nm were achieved. Pellets pressed from the nanopowders can be densified at a lower sintering temperature of 1150 °C, compared with 1475 °C by solid-state reaction method. The phase formation, microstructure, dielectric properties, and relaxor behavior of (1–x)BaTiO₃–xDyScO₃ were investigated systematically. With an increasing DyScO₃ doping concentration in BaTiO₃, a tetragonal to pseudo-cubic phase transition appeared at x = 0.03, and two different doping behaviors (donor or acceptor-type) of Dy³⁺ in (1–x)BaTiO₃–xDyScO₃ were discussed. The grain growth of BaTiO₃ ceramics was inhibited, and the grain size was decreased to 200 nm for x = 0.06. The dielectric peak was broadened and the curie temperature dropped gradually, accompanied by an increased room-temperature permittivity. Furthermore, a typical relaxor behavior was observed at x = 0.05 and 0.06, according to the modified Curie–Weiss law.