Excellence in Research: Understanding Structural, Magnetic, and Electronic Properties of Chromium Telluride

非技术摘要近年来，人们对绿色技术越来越感兴趣，因为绿色技术可以降低对不可再生能源的依赖，从而减少其对环境的影响。磁热材料是这一努力中正在探索的一类重要材料。这些材料在固态制冷、微致冷器、能量转换、磁泵、感应磁热和药物控制输送等方面具有潜在的应用前景。在这个项目中，我们研究了一种室温磁热材料--碲化铬，以了解它的磁性、电性和结构性质之间的关系。这项研究是在霍华德大学与国家实验室合作进行的，这使得霍华德大学的研究人员能够与外部社区建立密切的研究合作。霍华德大学是历史上最大的研究活跃的黑人大学(HBCU)，拥有大量历史上代表性不足的学生。因此，这项研究为未被充分代表的少数族裔学生带来了尖端的研究机会，并扩大了他们对材料科学研究的参与。这些研究人员正在接受高级材料科学研究、数据分析、模拟、科学写作和演示技能方面的培训。这将提高他们在学术界和工业界对潜在雇主的竞争力。技术摘要近年来，硫系铬化合物因其不同的磁性而引起了人们的极大兴趣。本项目研究了一种室温磁性材料--碲化铬，以了解其结构、磁性和电学性质之间的关系。这些研究包括单晶生长、磁学、热容、磁输运、同步加速器x射线散射和中子衍射研究，并辅之以基于密度泛函理论(DFT)的模拟。对分布函数进行了研究，以确定碲化铬结构随温度的演化。相干软X射线光谱学研究有助于确定其基态电子结构。此外，中子衍射研究有助于确定其磁序。该项目有助于回答与其磁结构相变相关的未解决的基本问题。此外，该材料还用于研究平行反常霍尔效应(PAHE)。因此，这项拟议的研究与Howard Forward的战略非常一致，该战略旨在为未被充分代表的少数族裔学生提供杰出的教育和研究经验，并吸引来自这些群体的下一代STEM学者。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical AbstractIn recent years, there has been an increased interest in green technologies, which can lower the dependence on non-renewable sources of energy, thus reducing their environmental impacts. Magneto-caloric materials are an important class of materials being explored in this endeavor. These materials have potential applications in solid-state refrigeration, micro-coolers, energy conversion, magnetic pump, induced magnetic hyperthermia, and controlled drug delivery. In this project, we study a room temperature magneto-caloric material, chromium telluride, to understand the relationship between its magnetic, electronic and structural properties. The research is performed at Howard University in collaboration with national laboratories, which enables Howard University researchers to forge close research collaborations with outside communities. Howard University is the largest research-active historically black university (HBCU), with a large historically underrepresented student population. Therefore, this research is bringing cutting-edge research opportunities to underrepresented minority students and is broadening their participation in materials science research. These researchers are being trained in advanced material science research, data analysis, simulations, scientific writing, and presentation skills. This will enhance their competitiveness with prospective employers both in academia and industry. Technical AbstractRecently, chromium chalcogenides have drawn much interest due to their diverse magnetic properties. This project studies one room-temperature magnetic material, chromium telluride, to understand the relation between its structural, magnetic, and electronic properties. The research includes single crystal growth, magnetic, heat capacity, magneto-transport, synchrotron x-ray scattering, and neutron diffraction studies, all supplemented by density functional theory (DFT)-based simulations. Pair distribution function studies are performed to determine the evolution of the chromium telluride structure with temperature. Coherent soft x-ray spectroscopy studies help determine its ground-state electronic structure. Furthermore, neutron diffraction studies help determine its magnetic ordering. This project helps answer unaddressed fundamental questions associated with its magneto-structural phase transitions. In addition, this material is used to explore the parallel anomalous Hall effect (PAHE). Therefore, this proposed research aligns well with the Howard Forward strategy of providing underrepresented minority students with exceptional educational and research experiences and attracting next-generation STEM scholars from such groups.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.