等価回路を用いたBaTiO₃微粒子の二重構造の解析

抄録

Double layered structure of submicron BaTiO₃ grains (0.1-0.6μm), in which the grain core is covered with a surface layer, has been analyzed using the equivalent circuit model. The observed permittivity of sintered pellets increases with increasing grain diameter. This agrees with a model in which the ferroelectric tetragonal core is covered with the paraelectric cubic surface layer. The best fit of this model to the observed permittivity has shown that the permittivity of the tetragonal phase is 5900 and that of cubic phase is 90. Also the thickness of the cubic surface layer in the sintered pellet has been estimated to be approximately 2nm, which agrees well with that estimated from the X-ray diffraction peak analysis.