New lead-free non-stoichiometric perovskite relaxor ceramics derived from BaTiO 3

• Published in: Solid state sciences Vol. 5; no. 11; pp. 1459 - 1464
• Main Authors: Simon, Annie, Ravez, Jean
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 2003
• Subjects: Dielectric studies; Lead-free relaxor ceramics; Lead-free relaxor ceramics; Dielectric studies
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/S1293-2558(03)00194-8

The present work concerns the preparation and dielectric characterization of some new non-stoichiometric lead-free ceramics with perovskite compositions derived from BaTiO 3. Lead-free compositions could be of great interest for environment-friendly applications (dielectric for capacitors, actuators, etc.). These materials have been shown to be either classical or relaxor ferroelectrics. In the first part of this article, the BaTiO 3Ba 0.5NbO 3 system concerns the cationic non-stoichiometry occurring only in the 12-coordination crystallographic site. In the second part, the influence of non-stoichiometry also occurring in the anionic site was determined in compositions belonging to the ternary system 2BaOTiO 2Nb 2O 5. The variation in the Curie temperature T C or the temperature T m of the maximum of ε′ r decreased when the composition deviated from BaTiO 3 and when the number of vacancies increased. On the contrary, the relaxor state was favored by such a deviation. Graphic