Materials World Network: Designed Preparation, Characterization, Magnetic Properties and Quantum Chemical Calculations of New Complex Itinerant Magnets, Ti(8-x)M(3+x)Ru(18-y)Rh(y)B

本项目将实验和理论结合起来，设计制备和随后的表征，并深入了解新的金属间铁磁体和反铁磁体。它是基于爱荷华州立大学和德国亚琛工业大学之间的合作。主要概念包括使用复杂的四维金属硼化物框架与磁性三维元素，如Cr， Mn, Fe， Co和Ni，插入到空隙中，以创建具有潜在低维特征的磁性结构。金属硼化物框架为磁性金属插入通道提供了结构坚固和电子健壮的网络。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机制。具体来说，通过x射线和中子衍射以及磁化实验来研究这些材料，以确定原子和磁性结构。在这些结构的各种模型上的电子结构的理论确定为进一步的原子取代合成工作提供了反馈，以创建具有目标磁性的新化合物。目前，化学家和材料科学家没有通用的、简单的规则来定位和裁剪铁磁性金属间化合物，即具有永磁性的金属化合物。这一努力使化学家能够研究单一结构家族中磁性行为的演变，从而确定随着各种化学和物理参数以系统的方式变化，磁性行为的趋势。像这样的项目，结合了凝聚态系统的实验和理论，为学生提供了一个真正的跨学科问题-这些学生学习不同的科学主题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参加这个项目的学生有机会进行交流，他们学习固态化学研究的实验和理论组成部分。此外，通过对结构族的系统研究，将产生一套针对金属永磁体的规则，这些永磁体具有许多技术应用。真正的挑战将是确定这样的目标材料将显示永久磁性行为的温度范围。总之，这一努力代表了一个强大的，协同耦合的实验和理论，目标是新的磁性材料，并可能导致新的材料具有不寻常的体磁性，由于磁性交换的潜在的一维特性。

This project combines experiment and theory towards the designed preparation and subsequent characterization and thorough understanding of new intermetallic ferromagnets and antiferromagnets. It is based on collaboration between Iowa State University and RWTH Aachen in Germany. 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 magnetic structures with potentially low-dimensional character. 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 are 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 provides 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 allows 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 learn how different scientific subjects and models impact other scientific areas. The student participants in this project in Aachen, Germany and Ames, Iowa have opportunities for exchange, and they learn both experimental and theoretical components of research in solid-state chemistry. Furthermore, through this systematic study of a structural family, a set of rules will be generated 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.