GOALI: Nanocrystalline Oxides For Integrated, Soft Magnetic Applications

该计划的科学目标是学习如何操纵纳米晶颗粒之间的磁耦合来创造软磁材料，在这种材料中，体磁性能，如磁场磁导率、磁化强度和矫直损耗可以独立变化。在整体材料中，这些特性并不是独立的。正在采取的方法是合成纳米晶磁性氧化物颗粒，并将其堆积成块状材料，通过成分、颗粒大小、形状和体积分数改变颗粒间的磁性耦合。最初，纳米铁氧体和稀土氧化物是通过反胶束过程合成的，它们的间距和堆积通过选择表面活性剂和溶剂来改变，以形成与电力转换器和相关设备相兼容的块状材料。这些材料在不同的阶段进行了表征，以确定体磁性能与纳米晶颗粒的性质及其磁耦合的关系。该计划的总体理由是评估纳米晶材料在DC-DC电力转换器中通过提高性能和减小物理尺寸来取代现有磁性材料的潜力。电源转换器广泛应用于整个电子行业，为几乎全数字电子产品和微处理器提供稳定的低压电源。只有随着具有更高磁导率和更低磁损的磁性材料的发展，才能实现对更小、更高功率、更高频率的DC-DC转换器的日益增长的需求。正在解决的挑战是如何使用纳米晶体颗粒创造新的磁性材料，这种材料可以被制造成一个集成的、功能强大的功率转换器，同时保持它们新颖的磁性组合。与罗克韦尔科学公司的合作为学生提供了电力设备磁性部件的设计经验，并有机会在开发过程中测试他们的候选材料。

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.