場所順のペロフスキートにおける平方座標mnの様々なバレンスの状態
Youwen Long1, Takashi Saito, Masaichiro Mizumaki
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. ywlong@msk.kuicr.kyoto-u.ac.jp
Journal of the American Chemical Society
|October 17, 2009
まとめ
研究者らは,AサイトオーダーされたペロブスキートLaMn3Cr4O12とLaMn3Ti4O12を合成した. 彼らは,A部位におけるマンガンのバレンスが変化し,マンガンがMn3+のみであるという長年の信念に異議を唱える可能性があることを発見しました.
科学分野:
- マテリアルサイエンス 材料科学
- 固体化学 固体化学
- クリスタログラフィーです.
背景:
- A-サイトオーダーペロブスキットは,ユニークな構造および電子特性を有する材料のクラスです.
- これらのペロフスキートの正方形座標Aサイトは,伝統的にJahn-Teller活性Mn3+) イオンと関連付けられています.
- ペロブスキットのイオンのバレンスの状態を理解することは,その性質を予測し調整するために不可欠です.
研究 の 目的:
- 新しいA位点配列ペロブスキット,特にラMn3Cr4O12とラMn3Ti4O12を合成し,特徴づけること.
- これらの合成化合物のA部位におけるマンガンイオンの有価状態を調査する.
- A場所のオーダーされたペロフスキートにおけるA場所のヤーン・テラー活動とMnのバレンスの確立された理解を再評価する.
主な方法:
- 高圧と高温の合成技術を使用して,標的のペロブスキート構造を取得しました.
- イオン構成を明らかにするために,化学式の決定と電荷状態の分析が行われました.
- 構造的およびバレンスの状態の分析には,おそらく光譜的または微分法 (暗黙的,明示的に述べられていない) が使用された.
主要な成果:
- LaMn3Cr4O12が合成され,特徴づけられ,LaMn3+) 3Cr3+) 4O12とMn3+) の電荷式をA地点で明らかにした.
- また,LaMn3Ti4O12も合成され,A部位で+2未満のマンガンのバレンスを示し,LaMn ((1.67+) ((3) Ti ((4+) ((4) O ((12)) の提案された電荷組合せを示した.
- これらの発見は,A部位におけるマンガンの有価性は,以前の仮定に反して,+3から+1.67まで幅があることを示しています.
結論:
- この研究では,要求の厳しい条件下で,新しいA-サイトオーダーペロフスキットを合成することに成功しました.
- この結果は,これらの材料のA位 Mnが独占的にMn ((3+) であるという長年の仮定に異議を唱えている.
- 観測された変数マンガンの有価性は,組成制御を通じてA位点順序のペロブスキットの特性を調節する可能性を強調しています.
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