Investigation of Magnetism in Discrete Rare-Earth Clusters and Low Dimensional Solids

本计画旨在研究离散稀土团簇与低维固体的磁性。在磁性材料中，4f矩提供了对硬永磁体的功能至关重要的内在磁各向异性。 我们的目标是调查的电子功能，是在2-，1-和0-维（簇）化合物和本地化（磁性）4f电子的离域（5D和6S）电子的特性之间的相互作用。稀土团簇和低维固体的研究，集成合成，性能测量，并有限使用计算方法的解释和理解的性能将被强调。 该项目建立在对稀土固体（主要是卤化物）的探索性合成研究的基础上，这些研究已经进行了三十年，但迄今为止对磁性的系统研究有限，几乎没有理论分析。 由于低维化合物通常表现出结构不稳定性（例如，1维和0维系统中的Peierls和Jahn-Teller扭曲，2维系统中的电荷密度波现象），将探索结构转变与磁转变一致的可能性，从而产生巨磁热材料的一阶磁转变特征。镧系元素在各种技术中发挥着重要作用-许多，也许是大多数，其中依赖于它们的f-电子在它们的化学中所起的独特作用。 它们的光学性质在含镧系激光材料中起着至关重要的作用。 在磁性材料中，镧系元素对硬永磁体的功能至关重要。 在这个项目中，我们将研究含镧系元素的分子是否可以作为分子磁体-最小的可想象的“条形磁体”。 如果是这样的话，含镧系元素的分子可以帮助提供纳米技术的信息存储容量，这将远远超过目前的硬盘驱动器技术。同样令人感兴趣的是其磁性、结构性质和热性质耦合的含镧系元素的材料。 这种材料有望用于新一代磁制冷机，其效率超过目前的制冷技术。对大学生、研究生和博士后研究员进行培训，使他们能够很好地竞争这些领域的工业和学术职位，仍然是一个优先事项。

This project aims to investigate magnetism in discrete rare-earth clusters and low dimensional solids. In magnetic materials, 4f moments provide intrinsic magnetic anisotropy that is central to the function of hard permanent magnets. The goal is to investigate the interplay between the electronic features that are characteristic of the delocalized (5d and 6s) electrons in 2-, 1-, and 0-dimensional (cluster) compounds and the localized (magnetic) 4f electrons. Studies of rare-earth clusters and low-dimensional solids that integrate synthesis, properties measurements, and limited use of computational methods for interpretation and understanding of properties will be emphasized. The project builds on the results of exploratory synthetic investigations of rare-earth solids (mostly halides) that have been ongoing for three decades, but which have so far seen limited systematic investigation of magnetic properties and almost no theoretical analysis. Since low-dimensional compounds often exhibit structural instabilities (e.g., Peierls and Jahn-Teller distortions in 1- and 0-dimensional systems, charge-density wave phenomena in 2-D), the possibility of structural transitions coincident with magnetic transitions will be explored, thus yielding first-order magnetic transitions characteristic of giant-magnetocaloric materials.The lanthanide elements play an important role in a variety of technologies - many, perhaps most, of which rely on the unique role that their f-electrons play in their chemistry. Their optical properties play an essential role in lanthanide-containing laser materials. In magnetic materials, lanthanides are central to the function of hard permanent magnets. In this project, we will investigate whether lanthanide-containing molecules might function as molecular magnets - the smallest conceivable 'bar-magnets'. If so, lanthanide-containing molecules could help provide nanotechnological information storage capacity that would far outstrip current hard-drive technologies. Also of interest are lanthanide-containing materials whose magnetic properties, structural properties, and thermal properties are coupled. Such materials are promising in a new generation of magnetic refrigerators with efficiencies that exceed current refrigeration technology. The training of students, undergraduate and graduate, as well as postdoctoral fellows, to compete well for industrial and academic positions in areas such as these continues to be a priority.