Materials World Network: Targeting New Complex Itinerant Magnets Using Experiment and Theory

材料世界网络：利用实验和理论瞄准新型复杂巡回磁体

• 批准号: 1209135
• 负责人: Gordon Miller
• 金额: $ 30万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1209135&HistoricalAwards=false
• 关键词: Materials; World; Network; Targeting; New

TECHNICAL SUMMARYThis Materials World Network project,supported by the Solid-State and Materials Chemistry program and the Office of Special Programs in the Division of Materials Research, combines synthesis, diffraction, magnetization measurements with first principles electronic structure theory to design and understand new intermetallic ferromagnets and antiferromagnets. Experimental activity will focus on complex 4d and 5d metal-boride frameworks with magnetic 3d elements, e.g., Cr-Ni, inserted in voids to create magnetic structures with low-dimensional character. The metal-boride framework is a structurally strong, electronically robust, and provides a mechanism for magnetic exchange between adjacent magnetic metal atoms via the spins on the conduction electrons. Previous support focused on structures with four-fold symmetry; new discoveries expand our studies to six-fold and three-fold symmetry, in which frustration effects can influence magnetic behavior. Specifically, atomic and magnetic structures will be determined by X-ray and neutron diffraction as well as magnetization experiments. Electronic structure theory will probe the energetics of various atomic and magnetic structures by evaluating orbital and exchange interactions to establish chemical rules and to calculate transition temperatures for ferromagnetic or antiferromagnetic behavior. Theoretical results will provide feedback for subsequent synthetic targets with predicted magnetic behavior. Theory will also investigate the magnetic structures and characteristics of the simpler MM'P and MM'As (M, M' = V-Cu), which also show tetragonal and trigonal symmetries. This work will establish the generality of the theoretical approach. At present, no general chemical rules exist to target compounds with permanent magnetic behaviour. The successful outcome will establish the evolution of magnetic behavior within a single structural family to identify trends in magnetic behavior as various chemical and physical parameters change in systematic ways. NON-TECHNICAL SUMMARYThis scientific effort combines experiment and theory to design and prepare new magnets belonging to a recently discovered family of metal-rich compounds. The complexity of these compounds allows chemical tuning, that can be accomplished by synthesis and can be studied by quantum chemistry. From this systematic study of a chemical family of compounds, a new set of rules will emerge for targeting metallic, permanent magnets, which have numerous technological applications. The real challenge will be to predict, via theory, the temperature range at which such targeted materials will show permanent magnetic behavior. The scientific effort will provide students a truly interdisciplinary problem, by combining chemistry and physics with experiment and theory. The student participants will clearly learn how different scientific subjects and approaches impact other scientific areas. The student participants from 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. In summary, this effort represents a strong, synergistic coupling of experiment and theory that will identify and characterize new magnetic materials, with the broader goal of establishing predictive rules for building newer magnets.

技术摘要材料世界网络项目，由固态和材料化学计划和材料研究部特殊计划的办公室支持，将合成，衍射，磁化测量与第一原理电子结构理论结合在一起，以设计和理解新的金属金属金属金属纤维网和反铁磁铁。 实验活动将集中在具有磁性3D元件的复杂4D和5D金属孔框架上，例如Cr-Ni，插入空隙中，以创建具有低维特征的磁性结构。金属孔框架是一种结构强的，具有电子功能的强度，并通过传导电子上的自旋提供了一种机制，可以在相邻的磁性金属之间进行磁交换。 以前的支持着重于具有四倍对称性的结构；新发现将我们的研究扩大到六倍和三倍的对称性，其中挫败感效应会影响磁性行为。 具体而言，原子和磁结构将由X射线和中子衍射以及磁化实验确定。 电子结构理论将通过评估轨道和交换相互作用来建立化学规则并计算铁电磁或反铁磁行为的过渡温度来探测各种原子和磁结构的能量。 理论结果将为随后具有预测磁性行为的合成目标提供反馈。 理论还将研究更简单的MM'P和MM'AS（M，M'= V-CU）的磁结构和特性，这些MM'P和MM'AS（M，M'= V-CU）也显示了四方和三角形对称性。 这项工作将确定理论方法的普遍性。 目前，尚无通用化学规则来靶向具有永久磁性行为的化合物。 成功的结果将建立单个结构家族中磁性行为的演变，以确定磁性行为的趋势，因为各种化学和物理参数在系统的方式上会发生变化。 非技术摘要这项科学工作结合了实验和理论，以设计和制备属于最近发现的金属富化合物家族的新磁铁。 这些化合物的复杂性允许化学调整，可以通过合成来完成，可以通过量子化学研究。 从对化合物的化学家族的系统研究中，将出现一套新的规则，用于靶向具有许多技术应用的金属，永久磁铁。 真正的挑战将是通过理论预测这种目标材料将显示永久磁性行为的温度范围。 科学的努力将通过将化学和物理学与实验和理论相结合，为学生提供一个真正的跨学科问题。 学生参与者将清楚地了解不同的科学学科和方法如何影响其他科学领域。 来自亚兴，德国和埃姆斯的学生参与者将有交流的机会，他们将学习固态化学研究的实验和理论成分。 总而言之，这项工作代表了实验和理论的强大，协同的耦合，它将确定和表征新的磁性材料，其更广泛的目标是建立用于构建新磁铁的预测规则。