新しい[Mn18]2+単分子磁石における磁化による量子トンネリング,s = 13
Euan K Brechin1, Colette Boskovic, Wolfgang Wernsdorfer
1Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, USA.
Journal of the American Chemical Society
|August 15, 2002
まとめ
この研究では,これまでにない最大のスピンと最も高い核性を有する単分子磁石 (SMM) [Mn18O14(O2CMe) 18 ((hep) 4 ((hepH) 2 ((H2O) 2) ((ClO4) 2 (1) ]という新しいマンガンのクラスターが報告されています. 低温で磁気化の量子トンネリング (QTM) を示しています.
科学分野:
- 無機化学 無機化学とは
- マテリアルサイエンス 材料科学
- マグネト化学 マグネト化学
背景:
- 単分子磁石 (SMM) は,ゆっくりとした磁気緩和を示す分子化合物です.
- スピン値が大きい高核性SMMの開発は,分子磁気学の進歩に不可欠です.
- 構造と磁気特性の関係を理解することは,新しいSMMを設計する上で鍵となるものです.
研究 の 目的:
- 新しい,高核性マンガネスクラスタを合成し,特徴づけること.
- 合成されたクラスタの磁気特性を調査し,単分子磁石としての可能性に焦点を当てます.
- この複合体における磁気化の量子トンネル化 (QTM) 現象を調査する.
主な方法:
- アセトニトリル中の特定のマンガンの前駆体との2− (((ヒドロキシエチル) ピリジン (hepH) の反応.
- コンプレックス [Mn18O14(O2CMe) 18 ((hep) 4 ((hepH) 2 ((H2O) 2) ((ClO4) 2) 1) の構造的決定のためのX線結晶学.
- 変動温度直流 (DC) と交流電流 (AC) の磁気感受性測定,磁気化研究,およびDC磁気化崩壊分析.
主要な成果:
- 2MnII,16MnIII複合体の分離 (1) は,中央のMn4O6ユニットと2つのMn7O9ユニットで,合計スピンS = 13.
- 単分子磁石の振る舞いの確認は,AC感受性研究と1.0K未満のヒステリシスの観察を通じて行われます.
- 14.8cm-1の有効リラクゼーションバリア (Ueff) の決定と0.25K以下の温度独立リラクゼーションの観測,磁気化の量子トンネル化 (QTM) を示す.
結論:
- コンプレックス1は,磁気化の量子トンネリング (QTM) を示す最大のスピンと最高核性単分子磁石 (SMM) を表しています.
- この研究は,重要な磁気特性を有する複雑な多核マンガネスクラスタの構築の実現可能性を示しています.
- この研究は,分子材料における磁気現象の基本的な理解と,高度な磁気システムの設計に貢献します.
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