**Polarization and Thermally Stimulated Processes in Lead-Free Ferroelectric Ceramics**

Aimé Peláiz-Barranco, Yuslín González Abreu, José de los Santos Guerra, Jinfei Wang, Tongqing Yang and Pierre Saint-Grégoire

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/60433

### **Abstract**

Over the last 20 years there has been an enormous effort in developing lead-free ferroelectric ceramics in order to obtain good dielectric, ferroelectric, piezoelectric and pyroelectric properties than those the conventional ferroelectric ceramics based on lead, such as lead zirconate titanate. An important group of lead free ferroelectric materials belong to the Aurivillius family, compounds which are layered bismuth [Bi2O2] 2+[An−1BnO3n+1] 2−. SrBi2Nb2O9 is a member of this family where the ferroelectric properties can be affected by the crystallographic orientation due to their anisotropic crystal structure. The divalent Sr cation located between the corner-sharing octahedra can be totally or partially replaced by other cations, most commonly barium. The chapter presents the analysis of the thermally stimulated current in Sr1-xBaxBi2Nb2O9 ferroelectric ceramic system with x = 0, 15, 30, 50, 70, 85, 100 at%. A numerical method is used to separate the real pyroelectric current from the other thermally stimulated processes. The remanent polarization is evaluated considering the hysteresis ferroelectric loops; the pyroelectric coefficient and the merit figure are evaluated too. Sr0.70Ba0.30Bi2Nb2O9 shows better ferroelectric and pyroelectric properties.

**Keywords:** Ferroelectrics, Aurivillius, Ceramics, Polarization, Pyroelectricity

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