Excellence in Research: Investigation of novel spin textures in non-centrosymmetric magnetic materials

在大多数固体中，对于单元格内（x,y,z）位置上的每个原子，在（-x,-y,-z）位置上都有一个不可区分的原子。这些材料被称为中心对称材料。然而，中心对称被破坏的磁性材料，称为非中心对称材料，由于其在未来纳米尺度量子信息技术中的应用潜力，近年来引起了相当大的关注。本项目的目的是利用中子散射技术研究非中心对称磁体的基本自旋和晶格性质。中子散射是一种强大的探针，可以确定非中心对称材料的自旋排列，这将使它们在未来的应用中具有潜在的用途。这项计划中的研究还将培训Prairie View A&amp；M大学（PVAMU）的下一代研究生和本科生进行中子散射测量和数据分析。此外，学生将学习如何培养单晶和低温物理的基本实验室技能。结合PVAMU，诺福克州立大学和莱斯大学的力量，共同努力将开发一个具有国际竞争力的项目，涉及新型复杂材料和中子散射的增长。本项目主要研究非中心对称磁性材料ScTMGe （TM = Fe, Mn, Co, Ni, Cu）、Mn掺杂ScFeGe和手性磁性氧化物的合成和表征。端元ScFeGe和ScMnGe均呈P-62m空间群的六角形结晶结构。ScFeGe是一个在~36 K以下的流动磁系统，其波向量K =(0 0 0.193)，磁矩≈0.53 μB，局限于ab面。当H平行于ab平面时，观察到一个阈值场为≈6.6 T的超磁跃迁。本研究计划的主要内容是制备上述材料的多晶形式和高质量单晶，然后对其物理性质进行表征，包括结构、相纯度的测定以及电子和磁性能的测量。本研究的实验结果将揭示材料的结构和磁性之间的相互关系。这些样品是在Prairie View， Rice和Norfolk州立大学合成的，然后对它们的物理性质进行表征，包括结构的确定，以及它们的电子和磁性质的测量。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical abstract In most solids, for every atom within the unit cell at position (x,y,z) there is an indistinguishable atom at (-x,-y,-z). These materials are called centrosymmetric materials. However, magnetic materials where the centrosymmetry is broken, termed noncentrosymmetric materials, have attracted considerable attention in recent years owing to their potential for future nanometer-scale quantum-information technology applications. The aim of this project is to study the fundamental spin and lattice properties of noncentrosymmetric magnets using neutron scattering technique. Neutron scattering is a powerful probe that can determine the spin arrangements of the noncentrosymmetric materials, which will allow their potential use for future applications. The planned research will also train the next generation of graduate and undergraduate students at Prairie View A&M University (PVAMU) for neutron scattering measurements and data analysis. In addition, students will learn how to grow single crystals and basic laboratory skills in low-temperature physics. The joint efforts by combining the strength of PVAMU, Norfolk State University, and Rice University will develop an internationally competitive program involving both the growth of novel complex materials and neutron scattering.Technical abstract This project focuses on the synthesis and characterization of non-centrosymmetric magnetic materials such as ScTMGe (TM = Fe, Mn, Co, Ni, Cu), Mn-doped ScFeGe, and chiral magnetic oxides. Both end members ScFeGe and ScMnGe crystallize in hexagonal crystal structure having P-62m space group. ScFeGe is an itinerant helimagnetic system below ~36 K with wavevector k = (0 0 0.193) and a magnetic moment ≈ 0.53 μB confined to the ab plane. A metamagnetic transition is observed with a threshold field of ≈ 6.6 T when H is parallel to the ab plane. The main element of this research plan is the preparation of the above listed materials in polycrystalline form and high-quality single crystals, followed by characterization of their physical properties, including determination of structure, phase purity and the measurement of their electronic, and magnetic properties. The experimental results obtained from this research will unveil the interrelationships between structural and magnetic properties of materials. The samples are synthesized at Prairie View, Rice, and Norfolk State University, followed by characterization of their physical properties, including determination of structure, and the measurement of their electronic, and magnetic properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.