Considerations for BaTiO3 Ceramics with High Piezoelectric Properties Fabricated by Microwave Sintering Method

概要

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A decrease in the domain size of barium titanate (BaTiO3) improves the piezoelectric constant ($d_{33}$). Other considerations suggest the high $d_{33}$ of BaTiO3 may be caused by the enhanced high dielectric constant ($\varepsilon_{33}^{\text{T}}/\varepsilon_{0}$) at room temperature due to the size effect. However, we have clarified that even a sample with a low $\varepsilon_{33}^{\text{T}}/\varepsilon_{0}$ shows high $d_{33}$ according to the optimization of microwave sintering conditions. We have verified that the $d_{33}$ of BaTiO3 ceramics fabricated by microwave sintering is as high as 370 pC/N despite the $\varepsilon_{33}^{\text{T}}/\varepsilon_{0}$ of 2100. Mechanisms affecting $d_{33}$ in microwave sintering and in conventional sintering of BaTiO3 are thought to be different. The relationship between the grain size, the mechanical quality factor $Q_{\text{m}}$, and the frequency constant $N_{\text{p}}$, which was obtained from microwave sintering, has assumed that a decrease in grain size causes a decrease in internal stress. We suggest that a decrease in internal stress induces continuity of strain in a grain boundary, resulting in continuity of domains across a grain boundary.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2008-11-25