Influence of core-shell structured grain on dielectric properties of cerium-modified barium titanate

✍ Scribed by Yung Park; Se Ahn Song

• Publisher: Springer US
• Year: 1995
• Tongue: English
• Weight: 840 KB
• Volume: 6
• Category: Article
• ISSN: 0957-4522
• DOI: 10.1007/bf00144638

✦ Synopsis

The dielectric properties and chemical inhomogenity of BaTiO3 ceramics sintered with additions of CeO2:1.5TIO2 were investigated using TEM XRD and EDS. Grains had three regions: grain shell severely doped with cerium, grain core BaTiO3 of greater purity, and a concentration gradient region where Curie temperatures were distributed. With decreasing temperatures, the volume fraction of ferroelectric domains in the concentration gradient region increased. Addition of CeO2:1.5TIO2 to BaTiO3 decreased the tetragonality (c/a ratio) and the grain size, and lowered the Curie temperature by approximately 30°C permol%. Even a small addition of 0.005 mol CeO2:1.5TiO2 to BaTiQ reduced the average grain size from 25 I~m to less than 1.25 #m and grains of an average grain size were completely doped with cerium, which explained why the 130 °C ferroelectric transition peak did not exist. The inhomogenity of the cerium concentration had a large influence on the dielectric temperature characteristic.