層状のマンガン酸化カルコゲニドの構造と性質のトポタキシ的酸化および還元制御
Geoffrey Hyett1, Nicolas Barrier, Simon J Clarke
1Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK.
Journal of the American Chemical Society
|August 21, 2007
まとめ
層層のオキシカルコゲニドのトポタクティックな改変により,その組成と磁気特性を制御することができる. 酸化は反鉄磁性秩序を強化し,還元はそれを破壊し,混乱と挫折につながります.
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
- マグネチズム (磁気) とは
背景:
- 層状のオキシカルコゲニドSr4Mn3O7.5Cu2Ch2 (Ch=S,Se) は,ペロブスキート型ストロンチウム・マンガン酸化物板と反フッ化物型銅カルコゲニド層を交互に特徴付けている.
- これらの化合物は,ペロブスキート板の中央層に本質的に酸化物が欠けていて,トポタクティック改変のためのユニークな場所を提供しています.
研究 の 目的:
- 酸化および還元によるSr4Mn3O7.5Cu2Ch2の頂上学的な変化を調査する.
- これらの改変が化合物の組成,構造,磁気特性に与える影響を理解する.
主な方法:
- フッ素化によるトポタクシー酸化.
- 酸素の脱インターケレーションによるトポタクティック・リダクション.
- 構造的および磁性特性の特徴.
主要な成果:
- フッ素化により,反鉄磁気順序温度と順序モメントサイズが増加した.
- 還元は,化学的混乱を導入することによって,磁界の長距離秩序を破壊した.
- 外側のペロブスキート層のマンガンの磁気モーメントは反鉄磁気順序を示し,中央層はスピンガラスのような振る舞いを示した.
結論:
- トポタクティック・モディフィケーションは,層状のオキシカルコゲニドの磁気行動を調整する経路を提供します.
- 酸化は磁気秩序を高め,減少は磁気相互作用の乱れと挫折につながります.
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