NSF-Europe Materials Collaboration: Rational Design and Quantum Chemistry of Complex Itinerant Intermetallic Magnets

这一奖项由爱荷华州立大学材料研究部的固体化学计划颁发，将实验和理论研究结合在一起，以设计新的金属间铁磁体和反铁磁体的制备和随后的表征。该提案是对材料世界网络公告NSF 04-599的响应而收到的，涉及使用具有磁性3D元素的复杂金属硼化物骨架，例如，插入在空隙中的具有低维特征的磁性结构。新的金属间化合物系列M9M‘2T18-XT’xB8(M和T代表金属元素；M‘具体表示磁性金属元素)将作为一种化学体系，其中价电子的数量可以被调节以诱导所需的磁性。爱荷华州立大学化学系的固态化学小组和亚琛RWTH无机化学研究所之间的这项合作代表了针对新磁性材料的实验和理论的强大、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。亚琛集团将扩展其目前的合成经验，使用经典的高温合成路线来合成这一新系列中的几种化合物，使用衍射方法和衍射分析对它们进行表征，并测量它们的磁性。爱荷华州立大学小组将使用电子结构包和化学键分析来了解这些复杂相的电子和磁性行为，并为亚琛小组预测新的合成目标。此外，ISU小组将进行与温度相关的单晶研究，以探索磁性行为结构变化的细节。两个小组将通过实验(中子衍射)和理论(自旋极化超晶胞计算)努力阐明新化合物的自旋结构。这个国际合作项目将结合凝聚态系统的实验和理论，并为学生和博士后助理提供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主题和模型如何影响其他研究领域。此外，在德国亚琛和爱荷华州艾姆斯参加这一项目的学生和博士后将有机会进行国际交流，他们将有机会学习固态化学研究的实验和理论部分。

This award by the Solid State Chemistry program in the Division of Materials Research to Iowa State University combines experimental and theoretical studies towards the designed preparation and subsequent characterization of new intermetallic ferromagnets and antiferromagnets. This proposal, received in response to the Materials World Network announcement NSF 04-599, involves the use of a complex metal boride framework with magnetic 3d elements, e.g., Cr, Mn, Fe, Co and Ni, inserted in voids that create magnetic structures with low-dimensional character. The new intermetallic series M9M'2T18-xT'xB8 (M and T represent metal elements; M' specifically indicates a magnetic metal element) will serve as a chemical system in which the number of valence electrons can be tuned to induce desired magnetic properties. This collaborative effort between solid-state chemistry groups at Iowa State University Chemistry Department and the Institute for Inorganic Chemistry at RWTH Aachen 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. The Aachen group will extend its present synthetic experience using classical high temperature synthetic routes to synthesize several compounds in this new series, characterize them using diffraction methods and diffraction analyses and measure their magnetic properties. The Iowa State group will use electronic structure packages and chemical bonding analysis to understand the electronic and magnetic behavior of these complex phases and predict new synthetic targets for the Aachen group. In addition, the ISU group will carry out temperature-dependent, single crystal studies to explore details in structural changes with magnetic behavior. Both groups will clarify the spin structures of the new compounds by experimental (neutron diffraction) and theoretical (spin-polarized super-cell calculations) efforts. This international collaborative project will combine experiment and theory for condensed matter systems, and provides student and post-doctoral associates with a truly interdisciplinary problem. These students will clearly learn how different scientific subjects and models impact other research areas. In addition, student and/or post-doctoral participating in this project in Aachen, Germany and Ames, Iowa will have opportunities for international exchange, and they will have opportunities to learn both experimental and theoretical components of research in solid-state chemistry.