T. Mitchell—contributing editor
Evidence of Cu Deficiency: A Key Point for the Understanding of the Mystery of the Giant Dielectric Constant in CaCu3Ti4O12
Article first published online: 10 JAN 2007
Journal of the American Ceramic Society
Volume 90, Issue 2, pages 638–640, February 2007
How to Cite
Fang, T.-T. and Mei, L.-T. (2007), Evidence of Cu Deficiency: A Key Point for the Understanding of the Mystery of the Giant Dielectric Constant in CaCu3Ti4O12. Journal of the American Ceramic Society, 90: 638–640. doi: 10.1111/j.1551-2916.2006.01419.x
This work was financially supported by the National Science Council of Taiwan under the Contract No. NSC-92-2216-E-006-010.
- Issue published online: 12 JAN 2007
- Article first published online: 10 JAN 2007
- Manuscript No. 21877. Received June 6, 2006; approved September 15, 2006.
The compositions of the grains and the grain boundaries in CaCu3Ti4O12 (CCTO) have been characterized by a high-resolution field emission transmission electron microscope equipped with a high-angle annular-dark-field detector and energy-dispersive X-ray spectroscopy (EDS). The excess ions and their clusters at grain boundaries led to the observed strain contrast. These ions are further clarified as Cu ions by Z-contrast (Z: atomic number) image and EDS. The quantitative EDS analyses further indicate that the grain boundaries of CCTO are Cu rich and the grains are Cu deficient. The Ca- or Ti-rich amorphous phases were observed at corners or edges of the grains of CCTO.