Ultrasonic and Dielectric Investigation of the (Sr, Pb) TiO₃–SPT Ferroelectric Ceramics

Ferroelectric materials have been extensively studied through their optical and dielectric properties. However, there are no many reports concerning simultaneously elastic and dielectric characterization. In this work, ferroelectric ceramics of SPT (x = 0.25) have been investigated by the ultrasonic pulse echo technique and dielectric measurements, as a function of the frequency and temperature. In the pulse echo technique, ultrasonic attenuation and velocity are obtained. The elastics constant stiffness was calculated from the ultrasonic velocity. The results obtained for dielectric and elastic modulus showed anomalies around the phase transition temperature, which can be correlated considering an elastic-electric linear coupling between strain and spontaneous polarization.

Keywords:

• Conductivity
• phase transition
• BaTio₃

Acknowledgments

The authors thank to FAPESP, CNPq, CAPES for the financial support and Francisco Picon for the technical support.

Paper originally presented at IMF-11, Iguassu Falls, Brazil, September 5–9, 2005