全有機バイナリ合金の磁気チューニングは,安定した2つのラジカルの間で行われます
Gonca Seber1, Rafael S Freitas, Joel T Mague
1Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Journal of the American Chemical Society
|February 11, 2012
まとめ
化および非化ベンジミダゾール窒酸化物の固体溶液は,調節可能な磁気特性を有する合金を形成する. これらの材料は,水素結合連鎖によって駆動される準一次元の鉄磁性行動を示します.
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:
- 2-(4,5,6,7-テトラフルオルベンジミダゾル-2-イル) -4,4,5,5-テトラメチル-4,5-ディヒドロ-1H-イミダゾル-3-オキシド-1-オキシル (F4BImNN) と2-(ベンジミダゾル-2-イル) -4,4,5,5-テトラメチル-4,5-ディヒドロ-1H-イミダゾル-3-オキシド-1-オキシル (BImNN) の混合物は,固体溶液である.
- これらの固体溶液は,組成 (x) に基づいて,異なる結晶学相 (オーソロンビックとモノクリニック) を表します.
研究 の 目的:
- F4BImNNとBImNNの二進体固体溶液の構造および磁気特性を調査する.
- 構成,結晶構造,磁気行動の関係を理解する.
主な方法:
- バイナリ固体溶液の合成と結晶化 (F4BImNN) (((x) ((BImNN) ((((1-x)).
- ユニット細胞構造を決定するX線結晶学.
- 磁気感受性の測定値は0.4Kから300Kです.
主要な成果:
- 固体溶液は,多種多様な構成で形成され,オルソロンビック (x < 0.8) とモノクリニック (x ≥ 0.9) の結晶構造を示します.
- 一次元 (1D) の水素結合連鎖が分子間パッキングを支配し,準1Dの鉄磁気交換 (J/k = 12-22 K) につながります.
- 低温 (0.4-1.2 K) で発生する反鉄磁性秩序は,鎖間交換が弱いため,鎖内交換より33~150倍弱である.
結論:
- オーソロンビックサンプルの磁気配列温度は,BImNN含有量の増加に伴い,線形的に上昇し,連鎖間の距離と交換相互作用の減少と相関する.
- モノクリニック・フェーズは,異なる連鎖間配列を示し,オートロロンビック・フェーズの傾向から逸脱する.
- 構成制御は,これらの準1D磁性材料の磁性特性を調節することを可能にします.
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