The nature and phase transition FRL–FRH in PZT doped with Nb

In the composition region of PZT rich in zirconium, (0.05 < x < 0.35) there are two phase transitions. The first takes place between the high and low temperature Rhombohedric phases FRL–FRH both of which are ferroelectric, and the second between the high-temperature ferroelectric Rhombohedric phase and the cubic phase which is paraelectric (FRH–PE). The phase FRL–FRH transition of the PZT system has been studies using different methods. In all of the cases, the fundamental difficulty in establishing the transition characteristics has been the small alteration in the electrical parameters of this transition. In this work, we have verified, when the samples being studied are polarized, the changes are intensified significantly, undoubtedly allowing both the characterization of the transition temperature and its nature. In order to carry out our study, we have selected several PZT compositions doped with niobium, by moving the Zr/(Ti + Nb) > 90/10 region, in which we have determined the characteristics of the transition phase and the influence of niobium on it.