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在高旋转铁中缓慢的磁放松(II) 复杂的复合体
Danna E Freedman1, W Hill Harman, T David Harris
1Department of Chemistry and Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|January 9, 2010
概括
研究人员发现了第一个单核铁 (II) 复合体,表现出单分子磁铁行为. 这个复合体表现出缓慢的磁放松,这对于开发分子磁性材料至关重要.
科学领域:
- 无机化学 无机化学 有机化学
- 材料科学 材料科学 材料科学
- 量子物理 量子物理是量子物理的基础.
背景情况:
- 单分子磁铁 (SMM) 对于开发高密度数据存储和量子计算至关重要.
- 单核过渡金属复合物正在积极研究SMM属性.
- 了解磁放松机制是设计高效的SMM的关键.
研究的目的:
- 报告第一个单核过渡金属复合体表现出单分子磁性行为.
- 为了研究一个高旋转铁的磁性和放松动力学特性和放松动力学.
- 阐明量子道和应用场在磁性放松中的作用.
主要方法:
- 三角形金字塔铁的合成和表征 (II) 复合物[tpa (Mes) ]Fe[-].
- 测量直流磁性易感性和磁化,以确定磁性异构性.
- 交流磁感应度测量以研究在变化直流场下的磁放松动态.
主要成果:
- 该复合体表现出缓慢的磁放松,这是单分子磁体行为特征.
- 对于S = 2基本状态,确定了一个强大的单轴磁性异构性 (D = -39.6 cm(-1))
- 在零应用直流场时观察到磁化的量子道化.
- 应用 1500 Oe DC 场启动了缓慢的磁放松,在高温下采用热激活机制,在低温下采用温度独立的道.
- 磁放松时间在1500 Oe左右达到最大.
结论:
- [(tpa(Mes))Fe](-) 是第一个单核过渡金属复合体,表现出单分子磁铁特性.
- 观察到的磁放松是由热激活过程和量子道的组合控制的,受应用直流场的影响.
- 这一发现为设计具有可调节性质的分子磁性材料开辟了新的途径.
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