V2OPO4における電荷順序と負の熱膨張
Elise Pachoud1, James Cumby1, Calum T Lithgow1
1Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh , Edinburgh EH9 3FD, United Kingdom.
Journal of the American Chemical Society
|December 21, 2017
まとめ
半等価オキシホスファートV2OPO4は605Kまでの電荷を示し,構造的移行と熱膨張のスイッチを示しています. 164K未満のフェリマグネティック・オーダリングと並行して,この新しい振る舞いを駆動します.
科学分野:
- 固体化学
- 材料科学
- マグネティズム
背景:
- チャージオーダーとその物質特性への影響を理解することは極めて重要です.
- 交換可能な熱膨張を持つ新材料の調査は重要な関心事である.
研究 の 目的:
- 半同価オキシホスファートV2OPO4の電荷の配列と熱膨張の性質を調査する.
- V-V結合,構造的移行,および熱膨張行動の関係を解明する.
- V2OPO4の磁気配列を調査する
主な方法:
- 構造分析のためのX線微分
- 熱膨張測定のための膨張計
- マグネティック・オーダリングの研究のための磁気感受性測定
主要な成果:
- 605Kまでの長距離V2+/V3+電荷の順番が観測された.
- 605Kでモノクリニックからテトラゴナル構造の移行
- 熱膨張をプラスからマイナスに切り替える.
- 164 Kの磁気順序転換の下のフェリ磁気順序
- 高温で局所的なスピンペアリングの相関を示す.
結論:
- 軌道上のポリマーチェーン内のV-V結合は,切り替え可能な熱膨張の鍵です.
- V-V結合の喪失は,高温で横断酸素運動が熱膨張を支配することを可能にする.
- V2OPO4は,電荷の順序,構造,磁気性の複雑な相互作用を示しています.
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