Roles of Ba/Ti Ratios in the Dielectric Properties of BaTiO3 Ceramics |
| |
Authors: | Jung-Kun Lee Kug-Sun Hong Jin-Wook Jang |
| |
Affiliation: | School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea;Department Materials Science and Engineering, University of California, Los Angeles, California 90095 |
| |
Abstract: | The effect of the Ba/Ti ratio on microstructure, dielectric/ferroelectric properties, and domain width was studied using optical microscopy, ?( T ) curves, D – E hysteresis, and transmission electron microscopy. Although Ti-excess samples showed abnormal grain growth and a decrease of room-temperature permittivity due to a liquid phase at grain boundaries, its ferroelectric properties were similar to those of stoichiometric BaTiO3 ceramics. However, in Ba-excess samples, an increase of permittivity and ferroelectric properties different from those of stoichiometry were found. Changes in domain width and ferroelectric transition behavior indicated that the variation of dielectric properties was related to the internal stress. It is proposed that this internal stress originated from differences in the thermal expansion coefficient between the matrix and the second phase. |
| |
Keywords: | dielectric materials/properties barium titanate |
|
|