Frustration and Spin Fluctuations in Itinerant Magnets

本项目由材料研究部凝聚态物理项目资助，提出了一种系统的方法来设计和发现属于一类罕见化合物的磁性材料，这些材料由非磁性成分形成：流动磁铁。磁性材料在我们的现代世界中无处不在，它们是许多技术的核心，包括记忆存储，磁共振成像（mri）等。虽然磁性材料的应用是明确的，但我们对其性质的基本理解在很大程度上仍然未知，特别是对于那些没有已知磁性元素（如铁或稀土）形成的磁性系统。对纯流动磁性极限的理解受到相关化合物的稀缺性的抑制，该项目寻求设计和合成。这种方法的另一个新颖之处是研究与晶体结构有关的流动磁体的效应。该提案支持培养晶体生长和材料表征领域的本科生和研究生研究人员。PI继续她正在进行的推广活动，其中包括在当地公立学校开放房屋和科学演示，以及开发新的“科学点菜”项目，旨在向年轻学生介绍复杂的科学概念。技术摘要：本NSF提案强调流动磁系统的实验研究，以探索自旋涨落和磁挫折在无磁性元素化合物中的作用。两个流动反铁磁体的新发现，以及已知的仅有的两个没有磁性元素的铁磁体，为两个主要的研究重点提供了一个平台：研究流动磁体的维数和自旋涨落之间的相关性，特别是在量子临界状态下；流动磁系统受挫新范例的发展。该项目解决了当前凝聚态物理的前沿问题，如量子临界性和随之而来的非费米液体效应，以及作为量子临界性广义相图的新维度的挫折。我们的项目符合社会对新材料设计和发现的迫切需求，同时培养新一代晶体种植者。PI继续她的项目，通过实验室“开放日”向公众提供动手科学体验，通过实习培训高中学生和教师，并在休斯顿地区的学校实施“科学点菜”项目。该项目提供符合学校科学课程的科学工具包，以及PI及其学生的演示和讲义，旨在促进课堂以外的学习。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 ABSTRACTThis project, supported by the Condensed Matter Physics program of the Division of the Materials Research, presents a systematic way to design and discover magnetic materials belonging to a rare class of compounds, those formed with non-magnetic constituents: itinerant magnets. Magnetic materials are ubiquitous in our modern world and they are at the heart of many technologies including memory storage, magnetic resonance imaging (MRIs) etc. While the applications of magnetic materials are clear, our fundamental understanding of their properties remains largely unknown, especially for those magnetic systems formed without known magnetic elements (like iron or rare earths). The understanding of the purely itinerant magnetism limit is inhibited by the scarcity of relevant compounds, which this project seeks to design and synthesize. An added novelty of this approach is the study of effects in itinerant magnets, related to the crystal structure. This proposal supports the training of undergraduate and graduate student researchers in the areas of crystal growth and materials characterization. The PI continues her ongoing outreach initiatives, which include open houses and science demonstrations at local public schools in addition to developing a new "science a la carte" program, aimed at complex science concepts accessible to young students.Technical abstract:This NSF proposal emphasizes experimental investigations of itinerant magnetic systems to explore the role of spin fluctuations and magnetic frustration in compounds without magnetic elements. New discoveries of two itinerant antiferromagnets, together with the only two known ferromagnets without magnetic elements, offer a platform for two main research thrusts: the study of correlations between the dimensionality and spin fluctuations of itinerant magnets, particularly in the quantum critical regime; the development of a new paradigm for frustration in itinerant magnetic systems. This project addresses issues currently at the forefront of condensed matter physics, such as quantum criticality and attendant non-Fermi liquid effects, and also frustration as a new dimension in a generalized phase diagram for quantum criticality. Our program aligns with the imperious societal need for design and discovery of new materials, while training the new generation of crystal growers. The PI continues her program providing hands-on science experience through the lab "open houses" for the public, training high school students and teachers through internships, and by implementing a "science a la carte" program for schools in the Houston area. This program provides science kits in line with the school science curriculum, together with demonstrations by the PI and her students, and handouts, aimed at fostering learning beyond the classroom.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.