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

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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.