Dielectric properties of Pb(Mg1/3Nb2/3)O3 and (Pb1−xLax)(Mg(1+x)/3Nb(2−x)/3)O3 ceramics prepared by columbite route

✍ Scribed by Adelina Ianculescu; Ana Brăileanu; Massimo Viviani; Liliana Mitoşeriu

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 593 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.02.168

✦ Synopsis

The role of the La-addition on the A-site of the perovskite Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) on the phase formation, microstructure and dielectric properties was investigated. Ceramic samples were obtained from PMN and (Pb 1-x La x )(Mg 1+x/3 Nb 2-x/3 )O 3 (PLMN) nanopowders synthesized by the columbite method using MgO and Mg-carbonate precursors. An influence on the degree of crystallinity and phase purity was found particularly in the PMN ceramics. Typical relaxor properties characterised by a diffuse phase transition with a maximum around 270 K and relaxation in the kHz range were observed. The incorporation of La induces the formation of a short range nanopolar ordered superstructure, thus modifying the dielectric relaxation properties, strongly depressing the permittivity. The observed behaviour is discussed in terms of microstructural characteristics induced by the Mg-precursor and of La-incorporation in the PMN perovskite unit cell.