Characterization of La-Doped PBN Ferroelectric Ceramics

In this work, pure and La³⁺-doped PBN56 ceramics (La³⁺ added from 0 wt% to 4 wt%) were fabricated and studied concerning its structure, microstructure and dielectric properties. The analysis of the microstructure of the ceramics showed a change of the grain morphology for ceramics with La content higher than 1.0 wt%. X-ray diffraction and Raman spectroscopy were performed to study the structure of the PBN56 ceramics. The results showed the presence of an orthorhombic phase, whose concentration is increased with the increasing of the La³⁺ content. The analysis of the results was performed to investigate the presence of the orthorhombic phase and the composition where its formation begins.

Keywords:

• Ferroelectricity
• niobates
• phase transitions
• Raman measurements

Acknowledgments

The authors thank CNPq and FAPESP (brazilian agencies) for the financial support and to the Prof. Ivonne P. Mascarenhas for XRD measurements. Also to Sr. Francisco J. Picon for the technical assistance.

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