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.

Keywords:

• Transmission electron microscopy
• base-metal-electroded capacitor
• X7R-type capacitor
• core-shell microstructure

Acknowledgments

Paper originally presented at AMF-4, Bangalore, India, December 12–15, 2003; received in final form April 10, 2005. The original Proceedings of the Fourth Asian Meeting on Ferroelectricity (AMF-4) are published in seven earlier volumes of FERROELECTRICS (Volumes 323–329, inclusive).