Influence of lanthanum doping on the morphotropic phase boundary of lead zirconate titanate

Abstract

A phase diagram for morphotropic ͑Pb 0.985 La 0.01 ͒͑Zr 1−x Ti x ͒O 3 is proposed based on a combination of X-ray and neutron powder diffraction experiments and complemented by transmission electron microscopy. Dependent on composition three regions are characterized. The stability range of tetragonal microdomains for high Ti contents, the stability range of rhombohedral microdomains for low Ti contents, and an intermediate stability range of nanodomains. All three regions exhibit a corresponding low temperature configuration. Temperature dependent diffraction revealed that lanthanum doping reduces the sensitivity of the structure to changes in temperature and composition. A continuous transition from pseudorhombohedral to tetragonal symmetry with an intermediate two-phase region at the morphotropic phase boundary is observed. A similar transition of low temperature superstructure phases from pseudorhombohedral to pseudotetragonal with an intermediate monoclinic phase governed by a continuous change in the oxygen octahedral tilt system from a − a − a − over a − a − c − to a 0 a 0 c − is identified.

Determination of depolarization temperature of (Bi1/2Na1/2)TiO3-based lead-free piezoceramics

“…Figure 5 presents temperature dependence of depolarization current density J depol and piezoelectric coefficient d 33 The d 33 of PZT decreases smoother than that of BT; this might be because of the existence of low symmetry nanopolar domains in PZT. 59 Coexistence of domains of a different structure allows for less abrupt accommodation of domain structure to temperature changes.…”

Statistical electric field and switching time distributions in PZT 1Nb2Sr ceramics: Crystal- and microstructure effects

“…For a comparable PZT 1La material, the diffraction intensity between the tetragonal peaks has been attributed to the presence of nanostructured domains. 31,33 The PZT 52.25/47.75 1Nb2Sr will be referred as t-morphotropic in the text.…”

Temperature-dependent synchrotron powder diffraction phase studies of (K0.37Na0.52Li0.03)(Nb0.87Ta0.1Sb0.03)O3ferroelectric ceramics

“…This unexpected behavior can either be due to strain from tetragonal domain growth or an artifact resulting from the residual anisotropic reflection broadening. This effect is well known for PZT and could be related to real structure effects from the microstructure [24,25] mics starting from 20 C to 400 C using a 20 C measurement step. Chemical analysis carried out on the sample showed that small amounts of Zr were introduced during the processing and that small amount of some volatile elements (Li, K and Sb) were lost after sintering.…”