The effect of Dy2O3 addition on crystal structure, grain growth, and dielec- tric properties in BaTiO3

The crystal structure, grain growth behavior, and dielectric properties of BaTiO have been studied with the addition of Dy O . The powders were synthesized at ratios of (100-x)BaTiO -xDy O (mol%, x = 0, 0.5, 1.0, 2.0) by a conventional solid-state synthesis, and the powder compacts were sintered at 1250 C for 2 hours in air. As the amount of added Dy O was increased, the crystal structure of the sintered samples changed from a tetragonal to a pseudo-cubic structure, and the tetragonality decreased. In addition, a secondary phase of Ba Dy Ti O appeared when Dy O was added. The average grain size after sintering decreased and abnormal grains appeared as the amount of Dy O increased. It can be explained that the grain growth behavior of the Dy O added-BaTiO occurs due to the two-dimensional nucleation and growth, and is governed by the interface reaction. Further, the correlation between crystal structure, microstructure, and dielectric properties was discussed.