化学圧力調節型バチオ3 薄膜で,自発的な極化が大きく,キュリー温度は高い
Yilin Wang1,2, Linxing Zhang1, Jiaou Wang3
1Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
Journal of the American Chemical Society
|April 26, 2021
まとめ
研究者らは,バリウムチタネート (BaTiO3) フィルムを強化するための新しい化学圧力方法を開発し,記録的な高フェロ電気性とキュリー温度を達成しました. この方法は,無鉛のピエゾ材料の改良のための有望な経路を提供します.
科学分野:
- 材料科学
- 固体物理学
- 鉄電化
背景:
- バリウムチタネート (BaTiO3) はよく知られている無鉛ピエゾ材料ですが,自発的偏振とキュリー温度に制限があります.
- 元素ドーピングを用いた既存の化学的圧力方法は,BaTiO3の特性を高めるのに限られた成功を収めている.
研究 の 目的:
- 高性能のBaTiO3フィルムのための促進された化学圧力経路を開発する.
- BaTiO3の鉄電性およびキュリー温度を大幅に高めること.
主な方法:
- 立方体 BaO と四角形 BaTiO3 の間の一貫した格子ストレスを介して負の化学圧力 (∼5.7 GPa) を課す.
- ストレスを利用して高テトラゴナリティ (c/a = 1.12) と大きなTiシフトを誘導する.
- Ba 5p-O 2pハイブリッド化とTi eg-O 2p結合を含む結合状態に対する負圧の影響を分析する.
主要な成果:
- BaTiO3フィルムで100μC/cm2の最も高い残留分極化 (Pr) を達成した.
- 1000 °Cを超える高キュリー温度 (Tc) を得ている.
- 化学的負圧下での結合状態が変化したため,極化が著しく強化されたことが示された.
結論:
- 推進された化学圧力の方法は,バチオ3の鉄電性と熱安定性を効果的に高めます.
- 負の化学圧力は,結合特性を変えることで,材料の性質を変更する上で重要な役割を果たします.
- このアプローチは,フェロエレクトリック以外の様々な機能的な材料の改善に一般的な可能性を秘めています.
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