Necessary Conditions for the Formation of {111} Twins in Barium Titanate |
| |
Authors: | Byoung-Ki Lee Sung-Yoon Chung Suk-Joong L Kang |
| |
Affiliation: | Materials Interface Laboratory, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Taejon 305-701, Korea |
| |
Abstract: | The experimental conditions for {111} twin formation in BaTiO3 were investigated. When BaTiO3 compacts without excess TiO2 were sintered either in an oxidizing atmosphere (air) or in a reducing atmosphere (95N2–5H2), no {111} twins formed within the BaTiO3 grains and no abnormal grain growth occurred. In contrast, many {111} twins were present within the abnormally grown grains in the excess-TiO2-containing BaTiO3 samples sintered in air, while no twins were observed in the excess-TiO2-containing samples sintered in 95N2–5H2. X-ray diffraction analysis showed that excess TiO2 forms a Ba6Ti17O40 phase during sintering with the space group A 2/ a in air and a Ba6Ti17O40? x phase with the space group C in 95N2–5H2. It appears therefore that excess TiO2 and an oxidizing atmosphere are necessary for {111} twin formation in BaTiO3. These results may also indicate that the interface structure between BaTiO3 and Ba6Ti17O40 influences the twin formation. |
| |
Keywords: | twinning barium titanate |
|
|