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体颗粒之间的磁耦合，以创建软磁材料，其中体磁性能，如磁场磁导率，磁化和矫顽力损失可以独立变化。在单片材料中，这些性质不是相互独立的。采用的方法是合成纳米晶磁性氧化物颗粒，并操纵其堆积成块状材料，通过组成、粒度、形状和体积分数来改变颗粒间的磁耦合。最初，铁氧体和稀土氧化物的纳米颗粒是用反胶束工艺合成的，它们的间距和填料随着表面活性剂和溶剂的选择而变化，形成与电力转换器和相关设备兼容的大块材料。在不同阶段对材料进行表征，以确定体磁性能与纳米晶颗粒的性质及其磁耦合之间的关系。该计划的总体理由是评估纳米晶体材料通过提高其性能和减小其物理尺寸来取代dc-dc电源转换器中现有磁性材料的潜力。电源转换器用于整个电子工业，为几乎全数字电子和微处理器提供稳定的低压电源。对体积更小、功率更高、频率更高的dc-dc变换器的日益增长的需求，只能通过提高磁导率和降低磁损耗的磁性材料的发展来实现。目前面临的挑战是如何使用纳米晶体颗粒制造新的磁性材料，这些材料可以被制造成一个集成的、功能性的电源转换器，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元件设计的经验，并有机会测试他们正在开发的候选材料。

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.