The Doping Effects of Intermediate Rare-earth Ions (Dy, Y and Ho) on BaTiO3Ceramics

The electrical property and microstructure in BaTiO 3 ceramics doped rare-earth ions with intermediate ionic size (Dy 3+ , Ho 3+ , Y 3+ ) were investigated.Microstructures have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD).Incorporation of rare-earth ions to BaTiO 3 ceramics depended on their ionic radius sensitively.Compared to Ho and Y ions, Dy ions provide BaTiO 3 ceramics with the high rate of densification and well-developed shell formation, due to their high solubility in the BaTiO 3 lattice, but the microstructure of Dy doped BaTiO 3 ceramics is unstable at high temperature, because Dy ions could not play a role of grain growth inhibition, leading to diffuse into BaTiO 3 lattice continuously after completion of densification during sintering.Comparing electrical property and microstructure, it is shown that the reliability of capacitor improved by high shell ratio.