单分子磁体行为多铁材料的设计合成及其磁、电性能研究

Multiferroic materials, with both simultaneous magnetic and electric ordering, have promising vision of applications in the field of temperature transmitte, information storage, mechanical drive, energy capture and spintronics, as well as valuable theoretical investigations. Up to now, the deep and wide research has been given to the pure inorganic complexes, while there is merely inorganic-organic hybrid complexes been reported. However, the inorganic-organic hybrid complexes have a lot of advantages compared to traditional pure inorganic one. Based on the analysis of the combination between molecule-based magnets (SMMs) and ferroelectrics, the new inorganic-organic hybrid multiferroic materials, which have both single-molecule magnetic and ferroelectric behaviors in a singular molecule, have been designed in this proposal. Considering the synthesis route of single-molecule magnets and the basic requirements of ferroelectric materials, the main design idea of this project has been made. Herein, the chiral amino acid and/or chiral Schiff bases ligads and lanthanide ions will be introduced to obtain the SMMs with polar point groups, and the detailed magnetic and ferroelectric properties will be investigated as well. Eventually, we are looking forward to showing a rare route to design inorganic-organic hybrid multiferroics with excellent performance as well as the relations between their structures and properties for the later research.

多铁材料是兼具磁有序和电有序的多功能材料，它在温度传感器、信息储存、机械驱动、能量捕获及自旋电子学等领域有着潜在的应用价值。目前人们对纯无机氧化物型多铁材料已有一定的研究，然而对具备更多优点的无机-有机杂化的分子基多铁材料的报道却很少。结合当代分子基磁体和分子基铁电体这两个领域的研究热点，本课题拟合成同时兼具单分子磁体和铁电体性质的无机-有机杂化分子基多铁材料。本项目的主要设计理念是结合单分子磁体的合成路线和铁电体的要求，以手性氨基酸和手性希夫碱为配体、Ln3+离子为金属离子合成结晶在极性点群的单分子磁体，并采用合适的测试手段研究其磁电性质。最后，总结出设计合成新颖无机-有机杂化的分子基多铁材料的方法，并对比实验结果、分析其磁构关系，为以后的研究打下基础。

本课题意在合成兼具单分子磁体和铁电体性质的无机-有机杂化分子基多铁材料，最终为得到电、磁双功能的分子基多铁材料开拓新思路。我们选取具有强磁各向异性的稀土离子为自旋载体(如镝离子)，通过溶剂调控和单晶到单晶的转换成功制备了五例镝单分子磁体和具有较大磁商值铁电体的毫米尺寸单晶。在一例六配位单分子磁体中首次观察到磁介电耦合效应；得到了两例室温铁电稀土镝单分子磁体，并对比了其磁介电耦合效应的差别和影响因素；制备了两例具有较大磁商变值的钆簇合物，其中一例呈现出铁电体行为。研究结果预示着在单分子磁体中也有望实现本征磁电耦合效应和调控分子极性，为最终实现电场对单分子磁体磁性的调控以及制备分子基多铁材料打开了一扇门。