標題: | Structural ordering transition and repulsion of the giant LO-TO splitting in polycrystalline BaSr1-xTiO3 |
作者: | Kuo, SY Liao, WY Hsieh, WF 光電工程研究所 Institute of EO Enginerring |
公開日期: | 1-十二月-2001 |
摘要: | We report Raman and x-ray diffraction studies of polycrystalline BaxSr1-xTiO3 (BST) prepared by the sol-gel technique in the range of x = 0 to 1.0. Other than a tetragonal to cubic phase transition at composition x approximate to0.75 of the BST powders detected by x-ray diffraction and Raman spectroscopy, a new structural ordering transition around x approximate to0.4-0.5 is observed due to the atomic arrangement. By taking the anharmonic coupling between the three A(1) (TO) modes into account, the observed repulsion of the giant LO-TO splitting is a result of decreasing cell dimension and strengthening the electron-phonon coupling. The results help us to explain the weakening of the ferroelectricity in the BST tetragonal phase as x decreases. The anomalous inconsistency in our experimental results and theoretical prediction are attributed to the lack of detailed information of dynamical effective charges in the BaxSr1-xTiO3 compounds. |
URI: | http://dx.doi.org/10.1103/PhysRevB.64.224103 http://hdl.handle.net/11536/29203 |
ISSN: | 1098-0121 |
DOI: | 10.1103/PhysRevB.64.224103 |
期刊: | PHYSICAL REVIEW B |
Volume: | 64 |
Issue: | 22 |
起始頁: | 0 |
結束頁: | 0 |
顯示於類別: | 期刊論文 |