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07:33
Quantifying Mixing using Magnetic Resonance Imaging
Published on: January 25, 2012
量子道和量子相干扰在一个[Mn(II) 2Mn(III) 2单分子磁铁中
Lollita Lecren1, Wolfgang Wernsdorfer, Yang-Guang Li
1Centre de Recherche Paul Pascal, CNRS UPR-8641, 115 av. du Dr. Albert Schweitzer, 33600 Pessac, France.
Journal of the American Chemical Society
|August 11, 2005
概括
这项研究合成了一种新的复合物,Mn4 (hmp) 6 (H2O) 2 (NO3) 2 (NO3) 2 (NO3) 2.2.5H2O,表现出单分子磁铁行为. 综合体显示了热激活和量子道放松,具有铁磁相互作用和定义的基本状态.
科学领域:
- 协调化学 协调化学
- 磁电化学 磁电化学 磁电化学
- 材料科学 材料科学 材料科学
背景情况:
- 单分子磁铁 (SMM) 是表现出缓慢磁性放松的分子.
- 了解多核星团内的磁相互作用是设计SMM的关键.
- 对于先进的磁性存储和量子计算应用来说,SMM的发展至关重要.
研究的目的:
- 合成和描述一个具有潜在SMM特性的新型集群.
- 为了研究合成复合物的磁相互作用和放松动态.
- 探索磁化量子道及其对SMM行为的影响.
主要方法:
- [Mn4(hmp) 6 ((H2O) 2 ((NO3) 2)) ((NO3) 2) 复合物的合成2.2.5H2O复合物通过涉及2-基甲基二和酸的反应.
- 单晶X射线衍射以确定Mn离子的晶体结构和协调环境.
- 测量直流和交流磁性易感度,以探测磁相互作用和放松过程.
- mu-SQUID磁力测量用于研究取决于场的磁化和SMM之间的相互作用.
主要成果:
- 晶体结构显示出一个双立方体[Mn4]核,其中有七度协调的Mn2+和六度协调的Mn3+离子.
- 在Mn2+-Mn3+和Mn3+-Mn3+对之间确定了铁磁相互作用,导致S(T) = 9基本状态.
- 该综合体表现出单分子磁铁行为,具有热激活放松 (阿雷尼乌斯定律) 和磁化在0.34K以下的量子道化.
- 量子相干扰测量证实了D值,并提供了横向异构和地面状态道分裂的参数.
结论:
- 合成的[Mn4]复合物是一种有前途的单分子磁体.
- 铁磁相互作用和量子效应的相互作用决定了观察到的磁性.
- 本研究提供了对高性能SMM的设计原则的见解.
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