Materials World Network: Targeting New Complex Itinerant Magnets M1-xM'1+x(TyT'1-y)2B2 using experiment and Theory

该项目是一项持续的赠款，它结合了实验和理论，旨在设计新的金属间磁体的制备和随后的表征并彻底了解它。主要概念涉及使用具有磁性3D元素的复杂的4D金属-硼化物骨架，例如，插入到空隙中的铬、锰、铁、钴和镍，以创建具有潜在低维特征的新的磁性结构，如本工作中研究的一维三角形。金属-硼化物骨架提供了用于将磁性金属插入通道的结构坚固和电子坚固的网络。此外，金属-硼化物结构本质上是金属的，这为相邻磁性金属原子之间通过传导电子上的自旋进行磁交换提供了一种机制。具体地说，这些材料将通过X射线和中子衍射以及磁化实验进行研究，以确定原子和磁性结构。从理论上确定这些结构的不同模型上的电子结构将为进一步的原子取代合成努力提供反馈，以创造具有靶向磁性行为的新化合物。目前，化学家和材料科学家没有通用而简单的规则来瞄准和定制铁磁性金属间化合物，即具有永久磁性的金属化合物。这一努力将使化学家能够研究单个结构家族内磁性行为的演变，以确定随着各种化学和物理参数以系统方式变化时磁性行为的趋势。像这样一个将凝聚态系统的实验和理论结合在一起的项目，为学生提供了一个真正的跨学科问题--这些学生将清楚地了解不同的科学学科和模型如何影响其他科学领域。在德国亚琛和爱荷华州艾姆斯，这个项目的学生参与者将有机会进行交流，他们将学习固体化学研究的实验和理论部分。此外，通过对结构族的系统研究，我们希望产生一套针对金属永磁体的规则，这些金属永磁体具有许多技术应用。真正的挑战将是确定这些目标材料将表现出永久磁性行为的温度范围。总而言之，这项工作代表了以新磁性材料为目标的实验和理论的强烈、协同耦合，并可能由于磁交换的潜在一维特征而导致具有不寻常的块状磁性的新材料。

This project, which is a continuing grant, combines experiment and theory towards the designed preparation and subsequent characterization and thorough understanding of new intermetallic magnets. The primary concept involves using a complex 4d metal-boride framework with magnetic 3d elements, e.g., Cr, Mn, Fe, Co and Ni, inserted in voids to create new magnetic structures with potentially low-dimensional character, like the one-dimensional triangles studied in this work. The metal-boride framework provides a structurally strong and electronically robust network for insertion of magnetic metals into channels. Furthermore, the metal-boride structure is intrinsically metallic, which provides a mechanism for magnetic exchange between adjacent magnetic metal atoms via the spins on the conduction electrons. Specifically, these materials will be studied by X-ray and neutron diffraction as well as magnetization experiments to determine atomic and magnetic structures. Theoretical determination of the electronic structures on various models of these structures will provide feedback toward further synthetic efforts of atomic substitutions to create new compounds with targeted magnetic behavior. At present, chemists and materials scientists have no general, yet simple, rules for targeting and tailoring ferromagnetic, intermetallics compounds, i.e., metallic compounds with permanent magnetic behaviour. This effort will allow chemists to study an evolution of magnetic behaviour within a single structural family to identify trends in magnetic behavior as various chemical and physical parameters change in systematic ways. A project such as this, that combines experiment and theory for condensed matter systems, provides students a truly interdisciplinary problem – these students will clearly learn how different scientific subjects and models impact other scientific areas. The student participants in this project in Aachen, Germany and Ames, Iowa will have opportunities for exchange, and they will learn both experimental and theoretical components of research in solid-state chemistry. Furthermore, through this systematic study of a structural family, we hope to generate a set of rules for targeting metallic, permanent magnets, which have numerous technological applications. The real challenge will be to identify the temperature range where such targeted materials will show permanent magnetic behavior. In summary, this effort represents a strong, synergistic coupling of experiment and theory that targets new magnetic materials, and may lead to new materials with unusual bulk magnetic properties due to the potential one-dimensional character of the magnetic exchange.