TEMPERATURE-COEFFICIENT IMAGE OF DIELECTRIC MATERIAL

Two dimensional images of the distribution of the relative values of t he temperature coefficient of the dielectric constant of a two phase c omposite ceramic composed of TiO2 and Bi2Ti4O11 are observed using a p hotothermal dielectric microscope. The images clearly show that each g rain of TiO2 has a negative temperature coefficient and each of Bi2Ti4 O11 a positive one, and that the macroscopic averaged temperature coef ficient of the ceramic is relatively small due to the cancellation of the coefficients with opposite signs.