Synthesis and characterization of pseudo-ternary Pb(Fe1/2Nb1/2)O3-PbZrO3-PbTiO3 ferroelectric ceramics via a B-site oxide mixing route

Abstract

Perovskite phase formation and dielectric/ferroelectric properties of the pseudo-ternary Pb(Fe1/2Nb1/2)O3-PbZrO3-PbTiO3 (PFN-PZ-PT) ferroelectric ceramics have been investigated as promising materials for multi-layer ceramic capacitors. Complete solid solution with pure perovskite phase can be formed in this system in the whole composition range studied using conventional solid-state reaction method via a B-site oxide mixing route. Crystal lattice of the ceramics obtained shrinkages with the increase of the concentration of Pb(Fe1/2Nb1/2)O3 (PFN) and expands with the increase of the content of PbZrO3 (PZ). With the increase of the concentration of PbTiO3 (PT), crystal structure of PFN-PZ-PT changes from pseudo-cubic ferroelectric phase to tetragonal one while retains the fraction of PFN as constant. A morphotropic phase boundary (MPB) forms at the composition of 42 mol% PT regardless of whatever concentration of PFN, and the content of PFN affects little on the composition of MPB. The preliminary phase diagram of the PFN-PZ-PT system is determined by X-ray diffraction (XRD) measurements combining with dielectric/ferroelectric characterization. Dielectric measurements indicate that the value of dielectric maximum (ɛm) and the temperature where ɛm appears (Tm) increase with the increase of the concentration of PT. However, PFN exhibits opposite effects, i.e., ɛm increases with the increase of the concentration of PFN accompanied by the decrease of Tm.