Dielectric Temperature Characteristics of Cerium‐Modified Barium Titanate Based Ceramics with Core—Shell Grain Structure

Various particle sizes of starting barium titanate were used to investigate the effect of chemical inhomogeneity on the dielectric temperature characteristics of a dilute solid solution of cerium-modified barium titanate. Transmission electron microscopy and energy dispersive spectroscopy confirmed three distinct areas in the modified barium titanate: a grain core, a grain shell, and gradient regions. The grain size and volume fractions of the grain core were somewhat proportional to the particle size of the starting barium titanate. The dielectric temperature characteristics will be explained in the present paper in terms of the three inhomogeneous regions. Actually, the dielectric temperature characteristics of the large grains (>3 μm) proved to be a function of variation in the T c values, whereas those of the small grains (<3 μm) were a function of both the T c values and the internal stress.