YBaCo2O5とLaBaCo2O5のトポタクティック還元:広角平面のC0I) を拡張された酸化物の中で
James Seddon1, Emmanuelle Suard, Michael A Hayward
1Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.
Journal of the American Chemical Society
|February 6, 2010
まとめ
コバルト酸化物YBaCo ((2) O ((5) とLaBaCo ((2) O ((5) のトポタキシ的還元により,アニオン欠乏構造が得られる. サイト内のカチオン順序とアイデンティティは,結果として生成された金属酸素ネットワークと調整環境を制御する.
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
- 無機化学 無機化学とは
背景:
- トポタクティック還元は,アニオン欠乏性酸化物を作るための重要な方法である.
- REBaCo ((2) O ((5-x) 段階のA位カチオン配列は,その構造的および磁性特性を影響する.
研究 の 目的:
- トポタクティカルに還元されたコバルト酸化物におけるA位カチオン順序と同一性直接アニオン空位順序の仕組みを調査する.
- 異常な調整環境を持つ新しいアニオン不足のコバルト酸化物構造を合成し,特徴づけること.
主な方法:
- NaHを用いた低温の減少.
- 構造分析のためのX線 difraktion.構造分析のためのX線 difraktion.
- 磁気感受性の測定. 磁気感受性の測定. 磁気感受性の測定. 磁気感受性の測定.
- 温度変数のニュートロン difraktion. ニュートロン difraktion. 温度変数のニュートロン difraktion.
主要な成果:
- YBaCo ((2) O ((4.5) とLaBaCo ((2) O ((4.25)) が合成され,異なるアニオン空位の有序構造を示した.
- YBaCo(2) O(4.5) には CoO(5) と CoO(4) の単位があり,LaBaCo(2) O(4.25) には CoO(5),CoO(4) と CoO(4) の正方形の平面単位が含まれている.
- 両化合物はそれぞれ280Kと325K未満の反鉄磁気配列を示し,LaBaCo(2)O(4.25はCo(I) センターの証拠を示している.
結論:
- Aサイトカチオン (Y3+とLa3+) の同一性と順序は,これらのコバルト酸化物におけるアニオン空白の秩序化された構造を決定する.
- オーダーされたAサイトカチオンは,アニオン空位を制御する経路を提供し,トポタクティック減少でオーダーします.
- この戦略は,ユニークな移行金属の協調幾何学を持つ新しい金属酸素フレームワークの準備を可能にします.
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