Collaborative Research: Dynamic Reversal Phenomena in Advanced Magnetic Nanostructures

NON-TECHNICAL SUMMARY This project is building an improved understanding of how magnetic nanomaterials behave when they are placed in a magnetic field that oscillates back and forth in time. Also known as magnetic relaxation, these behaviors depend on the properties of the material, including what elements comprise the material, as well as what geometric shape the material is formed into. Intellectual merit: By changing the ratio of the elements included, as well as the length and diameter of rod-shaped magnetic particles, this project is delivering new knowledge about how these core properties affect the time-varying magnetism response in these materials. This new understanding could ultimately enable the use of these materials in technologies that can identify, image, and treat cancer and other diseases, improve detection of magnetic effects and materials in industrial applications such as advanced manufacturing, and consumer applications such as home and food health and safety. Broader Impacts: A future workforce is being trained to discover and implement technology that can improve the health and well-being of U.S. citizens. Finally, this project is explaining why these materials are so important to audiences of all ages and interests across the state of South Carolina, which already manufactures many goods whose continued improvement depends on an understanding of the raw materials that enter these factories. TECHNICAL SUMMARY Dynamic relaxation in magnetic nanostructures, especially suspended in fluids, is very difficult to measure at frequencies higher than 100’s of kHz, and as a result, researchers in this field are left using an over-simplified ratios to combine physical (Brownian) particle relaxation with magnetic (Neel) relaxation in these particles. Intellectual Merit: By measuring relaxation over a wider range of frequencies and particle number, this project will deliver an improved expression that more accurately combines these relaxation contributions. In addition, by varying both the composition of the magnetic material, and the aspect ratio of cylindrical nanorods, the contribution of particle magnetism (i.e., magnetization, anisotropy, and uniformity) will be separated from that arising from interactions between the particles, e.g. in a fluid, delivering engineers information needed to properly design and specify magnetism and size for nanostructured magnetic systems to be used in applications ranging from medical imaging, diagnostics, and treatment, to industrial optimization of manufacturing precision, relying on magnetic sensing and measurement. Broader Impacts: A future workforce skilled in magnetic nanomaterials and measurement is being trained to work in these factories and clinics to improve the health and economic security of U.S. citizens. 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.