Theoretical Study on Interactions between Oxygen Vacancy and Doped Rare-Earth Elements in Barium Titanate

• Published in: Japanese Journal of Applied Physics 2011-09, Vol.50 (9), p.09NE01-09NE01-4
• Main Authors: Honda, Atsushi, Higai, Shin'ichi, Motoyoshi, Yasuhiro, Wada, Nobuyuki, Takagi, Hiroshi
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.50.09NE01

We performed first-principles theoretical calculations to examine the interactions between oxygen vacancy (V \text{O ) and rare-earth (RE) elements in barium titanate (BaTiO 3 ), in order to clarify the mechanism of V \text{O trapping by RE dopants, which affects the insulating reliability of BaTiO 3 -based multilayer ceramic capacitors (MLCC). It was found that V \text{O is stabilized at the first and second nearest O sites of RE at Ba site (RE \text{Ba ), and at the second nearest O site of RE at Ti site (RE \text{Ti ). The structural relaxations on bond lengths of RE \text{Ba --O and RE \text{Ti --O in BaTiO 3 , which are brought about by the existence of V \text{O at the above sites, decrease the total energy, and thus V \text{O is stabilized. Furthermore, we revealed that the stability of V \text{O increases with decreasing solution stability of RE dopants in BaTiO 3 . Accordingly, we concluded that RE dopants with higher solution energy in BaTiO 3 efficiently trap V \text{O , and thus the insulation reliability of MLCC is improved.