GOALI: Nanocrystalline Oxides For Integrated, Soft Magnetic Applications

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The scientific goal of the program is to learn how to manipulate the magnetic coupling between nanocrystalline particles to create soft magnetic materials in which the bulk magnetic properties, such as permeability in field, magnetization and coercive losses can be independently varied. In monolithic materials these properties are not independent. The approach being taken is to synthesize nanocrystalline magnetic oxide particles and manipulate their packing into a bulk material to alter, through composition, particle size, shape and volume fraction, the inter-particle magnetic coupling. Initially, nano-particles of ferrites and rare-earth oxides are being synthesized using inverse micelle processes and their spacing and packing varied through the choice of surfactants and solvents to form bulk material compatible with use in electrical power converters and related devices. The materials are characterized at different stages to determine how the bulk magnetic properties are related to the properties of the nanocrystalline particles and their magnetic coupling.The overall justification of the program is to assess the potential for nanocrystalline-based materials in replacing existing magnetic materials in dc-dc electrical power converters by enhancing their performance and decreasing their physical size. Power converters are used throughout the electronics industry to provide a stable, low voltage power supply to almost all-digital electronics and microprocessors. Increasing demands for smaller, higher power, higher frequency dc-dc converters can only be realized with the development of magnetic materials having improved permeability and lower magnetic losses. The challenge being addressed is how to create new magnetic materials, using nanocrystalline particles, which can be fabricated into an integrated and functional power-converter whilst preserving their novel combination of magnetic properties. The collaboration with Rockwell Scientific Company provides students with experience in the design of the magnetic components of power devices as well as the opportunity to test their candidate materials as they are being developed.