Structure and dielectric properties of Pb(Zn_(0.2)Ni_(0.8)_(1/3)Nb_(2/3)O_3-PbTiO_3 ferroelectric ceramic near the morphotropic phase boundary

摘要

The structure and dielectric behaviors of compositions near the morphotropic phase boundary (MPB) of (1-x)Pb(Zn_(0.2)Ni_(0.8))_(1/3) Nb_(2/3)O_(3-x)PbTiO_3 ceramics have been systematically investigated as a function of PbTiO_3 (PT) content. XRD experiments demonstrate that compositions with x = 0.26-0.38 lie in the MPB region of this ternary system. Dielectric behaviors of frequency dispersion and diffuse phase transition are gradually weakened with increasing PT content. Composition with x = 0.30 exhibits the maximum dielectric constant of about 24,500 at 1 kHz. Compared with Pb(Ni_(1/3)Nb_(2/3))O_3-PbTiO_3 system, the addition of Pb(Zn_(1/3)Nb_(2/3))O_3 in this study brings about the enlargement of the MPB region, the increase in the Curie temperature and the improvement of dielectric properties.