Dielectric properties and morphotropic phase boundaries in the xPb(Zn 1/3Nb2/3)O3-(1-x)Pb(Zr0.5Ti 0.5O3 pseudo-binary system

Ceramics in the xPb(Zn1/3Nb2/3)O 3-(1-x) Pb(Zr0.5Ti0.5)O3 [xPZN-(1-x)PZT] solid solution system are expected to display excellent dielectric, piezoelectric, and ferroelectric properties in compositions close to the morphotropic phase boundary (MPB). The dielectric behavior of ceramics with x = 0.1-0.6 has been characterized in order to identify the MPB compositions in this system. Combined with X-ray diffraction results, ferroelectric hysteresis measurements, and Raman reflectivity analysis, it was consistently shown that an MPB exists between x = 0.2 and x = 0.3 in this binary system. When x ≤ 0.2, the tetragonal phase dominates at ambient temperatures. In the range of x ≥ 0.3, the rhombohedral phase dominates. For this rhombohedral phase, electrical measurements reveal a profound frequency dispersion in the dielectric response when x ≥ 0.6, suggesting a transition from normal ferroelectric to relaxor ferroelectric between 0.5 ≥ x ≤ 0.6. Excellent piezoelectric properties were found in 0.3PZN-0.7PZT, the composition closest to the MPB with a rhombohedral structure. The results are summarized in a PZN-PZT binary phase diagram. © Springer Science + Business Media, Inc. 2006.