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掺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项目研究了高能量密度的无稀土合金纳米磁体，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实施，促进了新兴的绿色能源技术，并确立了美国在无稀土磁体开发方面的领导地位。该项目将能源关键纳米金属研究与材料科学和可持续纳米技术的令人兴奋的界面上的教育和推广相结合，鼓励代表性不足的少数民族追求独特的尖端磁性材料培训，并促进公众对可持续性和绿色能源中变革性磁性纳米技术的认识。类似的机会也是为高中科学教师设计的，部分是为了帮助他们更好地为高中生提供科学职业方面的建议。技术总结：这个CAREER项目旨在解决可持续的无稀土金属纳米结构的一个关键挑战：所有铁合金纳米磁体的能量密度主要取决于对它们的亚稳四元结构特性和掺杂剂分布的精确控制在原子尺度上。该项目的研究目标是了解控制四元铁合金的合成，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特性。该项目包括以下相互关联的活动：（1）利用相变合成四元铁钴纳米结构，（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，以及（3）硬磁和软磁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。除了对当地和地区教育的好处之外，该研究还对社会产生了重大的好处，因为成功的结果可能会导致无稀土永磁体的革命，并为绿色能源技术做出贡献。该奖项反映了NSF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 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.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.