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非従来の協調幾何学による強化されたイオンアニソトロピー:ヘプタコーディネートFe (II) を用いて設計された[{Fe (II) L}2{Nb (IV) (CN) 8}]螺旋鎖化合物の単鎖磁石の振る舞い
Thengarai S Venkatakrishnan1, Shaon Sahoo, Nicolas Bréfuel
1CNRS, Laboratoire de Chimie de Coordination, 205, route de Narbonne, F-31077 Toulouse, France.
Journal of the American Chemical Society
|April 13, 2010
まとめ
新しい1Dヘテロ核の鉄・ニオビウム化合物は,効率的な磁気交換カップリングと非従来のヘプタコーディネーションにより,単鎖磁石の振る舞いを表しています. このFe (II) -Nb (IV) 材料は,ヒステレスと磁気雪崩を含む驚くべき磁気特性を示しています.
科学分野:
- 協調化化学について
- マテリアルサイエンス 材料科学
- マグネティズム (磁気) とは
背景:
- シングルチェーン磁石 (SCM) は,ゆっくりと磁気放松を示す分子材料です.
- 強化された磁気特性を持つ新しいSCMの開発は,ナノテクノロジーのアプリケーションにとって非常に重要です.
- 鉄を基にしたSCMは広く研究されているが,効率的な磁気交換カップリングを達成することは依然として課題である.
研究 の 目的:
- 新しい1Dヘテロ核化合物を合成し,特徴づけること.
- 磁石の性質を調査し,単鎖磁石の振る舞いに寄与する要因を理解する.
- 先進的な磁気材料の設計における非従来の協調と磁気交換カップリングの可能性を調査する.
主な方法:
- Fe (II) とオクタシアノ金属酸 [M (CN) (8)) ] (M = Nb (IV)) を使用したシアノ橋渡された異金属鎖の合成.
- 1Dポリマー構造の構造的決定のためのX線 difraktion (単結晶および粉末).
- 磁気感受性,高場EPR,磁化,およびモスバウアー光譜法で,磁気行動とスピン相互作用を特徴付けます.
主要な成果:
- ヘプタコーディネーションと効率的な反鉄磁性 {Fe-Nb} 交換カップリング (J = -20 cm(-1)) を有する1Dヘテロ核 {Fe(II) Nb ((IV) } 化合物を合成した.
- 化合物は単鎖磁石の振る舞いを示し,緩やかな磁気放緩 (デルタ/kB) = 74 K,タウ0 = 4.6 x 10-11 秒) がある.
- 観測されたヒステレスループ, 4 kOeの強制場,低温での磁気雪崩プロセスは,重要な磁気アニソトロピーと効率的な交換を示しています.
結論:
- 非従来のヘプタコーディネーションと効率的な{Fe-Nb}磁気交換カップリングを組み合わせると,研究された1D化合物の驚くべき磁気特性が得られます.
- 観測されたSCMの振る舞い,ヒステリーシス,磁気雪崩は,強い交換相互作用とFe (II) ユニットの有意なアニソトロピーの相互作用に起因する.
- この研究は,調節可能な性質を持つ高度な分子磁性材料を設計するための有望な戦略を強調しています.
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