Ferroelectric characteristics of ytterbium-doped barium zirconium titanate ceramics

Ferroelectric characteristics of ytterbium-doped barium zirconium titanate (BZT in brief) ceramics have been investigated. It is found that ytterbium dopant greatly influences the dielectric properties of BZT ceramics. With the increase of ytterbium content, the Curie temperature is lowered by three apparent stages identified by the falling rate. and the relative permittivity maximum is enhanced and broadened enormously, The diffuseness of the ferroelectric phase transition for BZT is increased monotonously as well. The A,;B ratio in perovskite structure plays another important role on the ferroelectric phase transition characteristics for ytterbium doped BZT. The alternation of the substitution preference of ytterbium ions for the host cations in perovskite lattice seems to account for these effects. Thanks to the modifications of ytterbium on BZT, we developed a novel Y5V dielectric material with the room temperature dielectric constant over 23,000. and the dielectric strength higher than 4.0 kV/min under AC field, which can be used in manufacturing high voltage ceramic capacitors. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.