Structure and dielectric properties of Pb(Zn0.2Ni0.8)1/3Nb2/3O3-PbTiO3 ferroelectric ceramic near the morphotropic phase boundary

The structure and dielectric behaviors of compositions near the morphotropic phase boundary (MPB) of (1 − x)Pb(Zn0.2Ni0.8)1/3Nb2/3O3−xPbTiO3 ceramics have been systematically investigated as a function of PbTiO3 (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(Ni1/3Nb2/3)O3-PbTiO3 system, the addition of Pb(Zn1/3Nb2/3)O3 in this study brings about the enlargement of the MPB region, the increase in the Curie temperature and the improvement of dielectric properties.