Competition between Dipolar and Exchange Coupling in Fe19 High Spin Molecular Magnets

In a previous study of the S=35/2 Fe19 single molecule magnet we used WISH to get the 1.2 K ordering mode and LET to get the local field order parameter and magnetic excitations. Combining this data with Monte Carlo analysis we could deduce that, despite the presence of significant dipolar interactions due to the large spin, weak intermolecular interactions acting over distances of order 1 nm were the main factor controlling the ordering. To fully test this hypothesis, we need to shift the balance between dipolar and exchange interactions. Therefore, we propose to carry out measurements for a Fe19 molecule with larger etheidi ligands in order to quantify directly the effect of driving the system more strongly towards a dipolar-dominated limit. The end result will be valuable insight into the structural and spatial dependence of weak long-ranged intermolecular superexchange interactions.

在此前针对S=35/2的Fe₁₉单分子磁体（single molecule magnet）的研究中，我们借助WISH仪器获取了1.2 K下的有序模式数据，并通过LET采集了局域场有序参数与磁激发信息。结合蒙特卡洛（Monte Carlo）分析对该类数据进行整合后，我们得以推断：尽管该体系因大自旋特性存在显著的偶极相互作用，但以约1纳米尺度作用的弱分子间相互作用，才是调控有序化过程的核心因素。为全面验证这一假说，我们需要调整偶极相互作用与交换相互作用之间的平衡比例。为此，我们提议对搭载更大体积etheidi配体的Fe₁₉分子开展相关测量，以直接量化将体系更显著地推向偶极主导极限所产生的影响。本研究的最终成果，将为解析弱长程分子间超交换相互作用的结构与空间依赖性提供极具价值的认知视角。