对称性调控提升单分子磁体能垒的研究

项目名称： 对称性调控提升单分子磁体能垒的研究

项目编号： No.21201137

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 无机化学

项目作者： 郑彦臻

作者单位： 西安交通大学

项目金额： 25万元

中文摘要： 单分子磁体作为下一代高密度信息存储及处理材料受到极大的关注。目前，该类材料面临的挑战主要是可应用温度（也称阻塞温度，由自旋翻转能垒控制）过低。理论及许多实验结果表明造成自旋翻转能垒过低的一个原因是量子隧穿效应，但这可以通过对称性加以控制。理论上，严格具有三次轴对称性以上的分子并不存在量子隧穿效应。该项目的目标就是通过理性的选择配体选择，利用配体的高对称性及位阻效应，把多核或单离子配合物的对称性限制在特定的范围，从而把单分子磁体的能垒以及相应的可应用温度提高。与此同时，对有规律的体系进行系统的分析可以得到对称性对能垒掌控的深层机制，力争建立表达非3d过渡金属单分子磁体能垒的基本公式。

中文关键词： 单分子磁体；对称性；簇合物；磁各向异性；量子遂穿

英文摘要： Single-Molecule Magnets (SMMs) as expected next-generation high-density information storage and processing materials have attracted extensively attention. At present, this kind of material faces a major challenge of low application temperature (also known as Blocking Temperature, governed by the spin-reversal energy barrier). Many theoretical and experimental results show that the cause behind the low energy barrier of spin-reversal is Quantum Tunnelling (QT) effect, which can be well controlled by symmetry. Theoretically, a molecule that has a symmetry higher than the strict three-fold rotational axis should have no QT effect. This project aims at enhancing the energy barrier and applicable temperature of SMMs by judicious choice of ligand with high symmetry and stereo-hindrance effect that can effectively confine the symmetry of the molecule comprising of poly- or single-ion nucleus in certain range. Meanwhile,the systematic analysis of regular systems can help obtain the mechanism of symmetry controlled energy barrier, establishing the fundamental formulae of energy barrier of non-3d-transition metal SMMs.

英文关键词： single-miolecule magnets；symmetry；cluster；magnetic anisotropy；quantum tunneling