Grain Size Effect on Dielectric Properties of Ba 0.92 Ca 0.08 TiO 3 Ceramics

• Published in: Japanese Journal of Applied Physics 2013-09, Vol.52 (9S1), p.9
• Main Authors: Hoshina, Takuya, Furuta, Tsutomu, Yamazaki, Takahiro, Takeda, Hiroaki, Tsurumi, Takaaki
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.52.09KC05

We demonstrated the grain size effect on the dielectric properties of Ba 0.92 Ca 0.08 TiO 3 ceramics. Fine-grained Ba 0.92 Ca 0.08 TiO 3 ceramics with micrometer- and nanometer-sized grains were fabricated by the two-step sintering method and aerosol deposition method, respectively. The permittivity of Ba 0.92 Ca 0.08 TiO 3 ceramics increased with decreasing grain size when the grain size was more than 400 nm, whereas it decreased when the grain size was below 400 nm. The permittivity of Ba 0.92 Ca 0.08 TiO 3 ceramics with micrometer-sized grains was lower than that of BaTiO 3 ceramics. This was caused by the hardening of the soft mode and the decrease in the 90° domain-wall contribution by Ca substitution. Moreover, the grain size that gave the maximum permittivity for Ba 0.92 Ca 0.08 TiO 3 ceramics was lower than that for BaTiO 3 ceramics. This result suggested that the Ba 0.92 Ca 0.08 TiO 3 was less sensitive to the grain size effect than BaTiO 3 ceramics. These features in the grain size dependence of permittivity were explained by the tetragonal structure stability of Ba 0.92 Ca 0.08 TiO 3 .