Structural and Dielectric Properties of Nickel-Doped and Lanthanum-Chromium-Doped Barium Titanate Ceramics

• Published in: Japanese Journal of Applied Physics Vol. 41; no. Part 1, No. 11B; pp. 6926 - 6928
• Main Authors: Fukunaga, Mamoru, Li, Guobao, Uesu, Yoshiaki, Kohn, Kay
• Format: Journal Article
• Language: English
• Published: 01.01.2002
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.41.6926

Nickel-doped BaTiO3 (BaTi1-yNiyO3-d: BTN) and lanthanum-chromium double-doped BaTiO3 (Ba1-xLaxTi1-xCrxO3: BLTC) ceramics were synthesized and their symmetry and dielectric properties were studied. Samples were sintered at 1400 C in air from stoichiometric amounts of BaCO3 and other metal oxides. XRD data were obtained at 20 C. Dielectric properties were measured in the temperature range of 78 K to 453 K. With the increase of dopant ratio y, Curie temperature TC of BTN decreases, but when y exceeds about 0.01, a hexagonal phase appears and the dielectric constant becomes smaller. On the other hand, in the entire range of x, BLTC shows a perovskite structure and the compounds with larger x exhibit conductive rhombohedral or orthorhombic phases. In the range of x smaller than 0.1, BLTC shows a diffuse phase transition and a high dielectric constant with small tan d. The relaxor-like frequency dispersion was observed in BLTC at low temperatures. 7 refs.