CePd3+xGa8-xの構造と相変化: BaHg11構造型の新しい変種
Melanie C Francisco1, Christos D Malliakas, Robin T Macaluso
1Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
Journal of the American Chemical Society
|August 2, 2012
まとめ
立方体 BaHg11 構造型の新しい歪んだ変種が合成されました. これらのセリウム・パラジアム・ガリウム化合物は,可逆的な相変化と潜在的に複雑な磁気行動を示し,材料科学の研究に新たな道を開く.
科学分野:
- 固体化学 固体化学
- マテリアルサイエンス 材料科学
- クリスタログラフィーです.
背景:
- 立方体 BaHg11 構造型は,新しい材料合成の基礎として機能します.
- 構造的変化と相変化を理解することは,新しい機能的材料の開発に不可欠です.
研究 の 目的:
- BaHg11構造型の新しい歪んだ変異を合成し,特徴づけること.
- CePd3+xGa8-xとその稀土類の構造特性,相変化,および潜在的な物理現象を調査する.
主な方法:
- Ga fluxで新しい化合物の合成.
- 構造的決定のためのX線 difraktion (粉末と単結晶).
- 位相変遷の研究のための微分熱分析と温度依存のX線微分 in situ.
- 物理特性分析のための磁気感受性,電気抵抗性,熱容量測定.
主要な成果:
- 多数のCePd3+xGa8-x相の合成が成功し,合成条件によって異なる構造 (オーソロンビック,ロンボエドール,立方体) を有する.
- 低温オーソロンビック/ロンボエドールと高温立方体の間の約640°Cの可逆相変化の観測.
- 構造分析は,カゴメのようなCe原子配列を含む,BaHg11型からのわずかな歪みを明らかにしました.
- 希土類 (REPd3+xGa8-x) が合成され,より低い対称性の空間群で結晶化した.
- 物理的な性質における低温の異常は,コンドの存在,結晶の電気場,磁気挫折効果を示唆する.
結論:
- BaHg11構造型,特にCePd3+xGa8-xとその類似体の新しい歪んだ変種が成功裏に合成されました.
- これらの材料は,リバーシブルな相変遷や,親構造からの歪みを含む複雑な構造的振る舞いを表しています.
- 観測された物理的性質は,複雑な電子と磁気相互作用を示し,さらなる調査を正当化しています.
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