Size dependence of THz region dielectric properties for barium titanate fine particles
Barium titanate (BaTiO3) crystallites with various particle sizes from 22 to 500 nm were prepared by the two-step thermal decomposition method of barium titanyl oxalate. Various characterizations revealed that these particles were impurity-free, defect-free, dense BaTiO3 particles. The powder dielectric measurement clarified that the dielectric constant of BaTiO3 particles with a size of around 58 nm exhibited a maximum of over 15,000. To explain this size dependence, the THz region dielectric properties of BaTiO3 fine particles, especially Slater mode frequency, were measured using the far infrared (FIR) reflection method. As the result, the lowest Slater mode frequency was obtained at 58 nm. This tendency was completely consistent with particle size dependence of the dielectric constant.
KeywordsTHz region dielectric property Barium titanate Fine particle Infrared reflection
We would like to thank Mr. M. Nishido of Fuji Titanium Co., Ltd. for preparing high purity BaTiO(C2O4)2·4H2O. This study was partially supported by (1) a Grant-in-Aid for Scientific Research (15360341) from the Ministry of Education, Science, Sports and Culture, Japan and (2) the Ookura Kazuchika Memorial foundation.
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