Microwave Dielectric Dispersion in (Pb,La)TiO₃ Ferroelectric Ceramics

Abstract

A detailed study of dielectric relaxation phenomenon has been carried out in ferroelectric ceramics based on PbTiO₃ system with composition Pb_(1-x)La_(x)TiO₃ (x = 0.15 and 0.27) in the microwave frequency region. The experimental results showed a strong dielectric dispersion on both normal (x = 0.15) and relaxor (x = 0.27) ferroelectric compositions, which appears not only in the ferroelectric phase, but also in the paraelectric one far above the transition temperature. The characteristic frequency increases quickly with the lanthanum content in samples.

Keywords:

• Microwave
• dielectric dispersion
• ferroelectricity
• lead titanate

Acknowledgements

The authors thank to CAPES, CNPq and FAPESP Brazilian agencies for financial support. The authors also thank Mr. Francisco J. Picon (DF-UFSCar) for technical assistance.