TEM microstructures of X7R type base-metal-electroded BaTiO3 capacitor materials co-doped with MgO/Y2O3 additives

In this report, how the MgO/Y2O3 additives modify microstructure and hence the dielectric constant-temperature (K-T curve) properties of the BaTiO3 materials was examined using transmission electron microscope (TEM). TEM investigation indicates that the dielectric constant-temperature (K-T curve) properties of the materials vary with the processing parameter pronouncedly, which is presumed mainly due to the growth of the grains during sintering, altering the core-shell microstructure for the materials. Furthermore, the shell is not uniformly surrounding the core and the shell thickness varies among the grains of BaTiO3 materials. Such a phenomenon is presumed to be the prime factor resulting in the fluctuation of dielectric properties of these materials with the processing parameters.