低座標コバルト中心を特徴とする四核単分子磁石における大きなアニゾトロピー障壁
Khetpakorn Chakarawet, Philip C Bunting, Jeffrey R Long1
1Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|January 24, 2018
まとめ
この研究では,安定した高スピン状態と遅い磁気緩和を示すコバルトクラスター化合物を合成した. この研究は,移行金属クラスターにおける磁性アニソトロピーの強化のための戦略として,低座標金属センターの結合を強調しています.
科学分野:
- 無機化学
- 材料科学
- マグネト化学
背景:
- 低座標の金属の中心は 独特の磁気特性に欠かせない.
- 金属中心間の電子通信を理解することは 磁気緩解を制御する鍵です
研究 の 目的:
- 四核コバルトクラスター化合物の合成と特徴付け
- 電子通信が緩やかな磁気緩和に及ぼす影響を調査する.
- 移行金属クラスターにおける磁性アニソトロピーの強化のための戦略を探求する.
主な方法:
- [FeCp2][B(C6F5) 4を用いた Co4 ((NPtBu3) 4) の化学酸化.
- dc と ac の磁気感受性の測定を用いた磁気特性.
- オーバック,量子トンネリング,ラマンプロセスを通して磁気リラックスダイナミクスの分析.
主要な成果:
- 合成された [Co4 ((μ-NPtBu3) 4 ] [B ((C6F5) 4 ] 化合物は,分離された S = 9/2 基底状態を 300 K まで表している.
- 磁場が加わらない状態で,ゆっくりとした磁気放緩が観察された.
- 87cm−1の効果的なスピン逆転バリアが決定され,これは移行金属クラスターで最大である.
- 3. 6K以下では磁気ヒステレスとブロックが観察された.
結論:
- 金属と金属の軌道が重なり,安定した高スピン基底状態に寄与する.
- 低座標の金属中心の結合は,磁性アニソトロピーを効果的に強化し,磁気放松を遅らせる.
- この研究は,移行金属クラスターに基づく高度な磁気材料の開発のための有望な戦略を示しています.
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