CAREER: Rare-Earth-Free All Ferrous Nanomagnets Towards High Energy Density

非技术总结：目前通过在金属合金中加入稀土元素来提高永磁体的能量密度。替代不可持续和战略上不受欢迎的稀土元素是最关键的挑战之一。这个CAREER项目研究高能量密度的无稀土合金纳米磁铁，完全基于传统元素Fe， Co和Ni。该项目的成功消除了环境上不可持续的稀土应用，促进了新兴的绿色能源技术，并确立了美国在无稀土磁铁开发方面的领导地位。该项目将能源关键型纳米金属研究与材料科学和可持续纳米技术的教育和推广结合起来，鼓励未被充分代表的少数群体追求独特的尖端磁性材料培训，并培养公众对可持续性和绿色能源中革命性磁性纳米技术的认识。为高中科学教师设计了类似的机会，部分原因是为了帮助他们更好地为高中生提供有关科学职业的建议。技术概述：本CAREER项目旨在解决可持续无稀土金属纳米结构的关键挑战：所有铁合金纳米磁体的能量密度主要取决于对其亚稳四方结构性质和原子尺度上掺杂物分布的精确控制。本项目的研究目的是了解控制四方铁合金的合成、掺杂和自组装的基本参数，并探索其独特的高能量密度纳米磁体的交换耦合性能。该项目包括以下相互关联的活动：(1)利用相变合成四方铁钴纳米结构；(2)利用化学转化和界面扩散合金化探索单畴铁镍的掺杂和有序-无序转变；(3)磁性硬软铁纳米复合材料的交换耦合，以获得高能量密度的无稀土纳米磁体。除了当地和区域的教育效益外，这项研究还为社会带来了重大利益，因为成功的结果可能导致无稀土永磁体的革命，并为绿色能源技术做出贡献。

Non-Technical Summary:Increases in energy density of permanent magnets are currently achieved through the incorporation of rare earth elements into the metal alloys. Replacing non-sustainable and strategically undesirable rare-earth elements is one of the most critical challenges. This CAREER project investigates rare-earth-free alloy nanomagnets for high energy density, based exclusively on traditional elements Fe, Co and Ni. The success of this project removes environmentally non-sustainable rare-earth implementations, promotes emerging green energy technologies, and establishes U.S. leadership in rare-earth-free magnet development. The project integrates energy-critical nanometal research with education and outreach at the exciting interface of materials science and sustainable nanotechnologies, which encourage underrepresented minorities to pursue unique cutting-edge magnetic material training, and fosters the public awareness of transformative magnetic nanotechnology in sustainability and green energy. Similar opportunities are designed for high-school science teachers, in part to help them be better equipped for advising high school students about science-based careers.Technical Summary: This CAREER project aims to address a key challenge of sustainable rare-earth-free metallic nanostructures: the energy density of all ferrous alloy nanomagnets is dictated chiefly by the precise control of their metastable tetragonal structural properties and dopant distribution on the atomic scale. The research objective of this project is to understand basic parameters that govern synthesis, doping and self-assembly of tetragonal ferrous alloys and to explore their unique exchange-coupling properties for high energy density nanomagnets. The project is comprised of the following interrelated activities: (1) synthesis of tetragonal iron-cobalt nanostructures using phase transformations, (2) exploring the doping and order-disorder transition of single domain iron-nickel using chemical transformation and interfacial diffusion alloying, and (3) exchange-coupling of magnetically hard and soft ferrous nanocomposites to achieve high energy density rare-earth-free nanomagnets. Beyond the local and regional educational benefits, the research entails a major benefit to society in that successful results could lead to the revolution of rare-earth-free permanent magnets and contribute to green energy technologies.