The PZT system (PbTixZr1–O3, 0≤x≤1.0): The real phase diagram of solid solutions (room temperature) (Part 2)

Refined phase portrait of the rhombohedral region of the x–T diagram of the Pb(Zr1–x Ti x )O3 system and singularities of dielectric spectra of its solid solutions

“…The behavior of the dependences ε/ε 0 (T) and tanδ(T) of the SS with x = 0.14 strongly changes; as was shown in [21,23], in this SS, clusters of the T-phase are already present. This leads to the rise of strongly blurred maxima of ε/ε 0 (T) at the point of transition to the paraelectric phase at low frequencies of the measuring field and to dispersion of ε/ε 0 (T) at temperatures below the phase transition temperature.…”

“…From our results of analysis of the crystal structure and electrical properties of ceramics of the considered system in the interval of concentrations 0 ≤ x ≤ 1.00 and temperatures 25°C ≤ T ≤ 700°C, the x-T phase diagram with allowance for the real SS structure were constructed [17,[20][21][22]. This structure is caused by the existence of domain and interphase boundaries, clusters of new phases, and extended planar defects arising due to the variable valence of Ti, which provokes the formation, accumulation, and ordering of oxygen vacancies and their removal by a crystallographic shear.…”

“…As a result, it was found that the phase portrait includes not only the generally known phases and morphotropic phase transition regions (MPTR), but also fragments of the phase diagram inside uniaxial fields with various phase states (PS) of solid solutions, which are characterized by different but very close cell parameters in regions of their coexistence. However, the high-temperature X-ray diffraction experiments from which the phase diagram has been constructed in [17] were performed with a larger concentration step than the experiments at room temperature in [21], which has led to inconsistency in the determination of the phase states of some SSs from the Rh region. In addition, it proved to be impossible to uniquely determine the position of the R3c → R3m transition curve.…”

Effect of nonstoichiometry on the structure and dielectric properties of bismuth ferrite

“…Figure 1 shows the above structural parameters as functions of x. It can be seen that the experimental val As we showed in [2,8,9], the behavior of the dependences of the structural characteristics in Fig. 1 is typical of other perovskite compounds and their solid solutions with deficiencies of the А positions.…”

Two phase diagrams of Pb(Ti0.485Zr0.515)0.98(Nb0.5Bi0.5)0.02O3 solid solution in the temperature range 20 ≤ t ≤ 600°C

“…The reasons for the former anomaly were described in detail in [5]; it was shown therein that the volume is constant due to two competing processes: temperature expansion and structure compacting in the crystallographic shear planes (CSPs). The latter are the main planar defects in the real structure of Pb(Ti x Zr 1 -x )O 3 (PZT) solid solutions [6] and other solid solutions having a ABO 3 perovskite structure and containing ions with variable valence (such as Ti [7] or Nb [8]) in B sites. The latter anomaly will be explained below.…”