Ferroelectric systems based on Pb(Zr1–yTiy)O3, are probably one of the most investigated materials due to their excellent physical properties, which can even be easily improved when modified with some chemical additives. Such substitutions provide some relevant characteristics in the piezoelectric, ferroelectric and pyroelectric responses. For specific compositions, a strong frequency dependence of the dielectric properties, well known as the relaxor behavior, can be observed, which has attracted the attention of the researchers because of the exciting physical characteristics revealed by these systems. The present work aims a careful investigation in the dielectric properties of rare-earth (RE) modified PZT ferroelectric ceramics. In particular, the relaxor behavior and the characteristics of the phase transition have been studied in details as a function of the RE content. The obtained results were analyzed within the framework of the models proposed in the current literature.
The authors wish to thank FAPEMIG and CNPq Brazilian agencies and NSF (Grant No. ECCS1002380) for the financial support.