Frequency Agile Devices Based on Stimuli-Active Magnetic Nanowire Composites

本研究的目的是开发新型的频率捷变互易（可调谐滤波器）和非互易（隔离器和环行器）微波器件的基础上的刺激响应磁性纳米线复合材料。在现代世界，当无线连接保证提供语音，视频和数据访问？任何人任何地点任何时间对远程可调谐微波设备的需求一直存在。该研究将整合磁性纳米线的制造，频率捷变微波器件的设计，表征和建模。半个多世纪以来，铁氧体一直是？工作狂？微波器件，特别是非互易应用。铁氧体的主要优点是，它们提供了一个非常高的电阻率与合理的良好的磁性能，这是非常重要的，在高频查看涡流？电流损耗然而，它们的平均磁性能对基于铁氧体的微波器件的尺寸和重量产生负面影响。刺激响应性磁性纳米线复合材料将联合收割机结合磁性纳米线的上级电磁性能所提供的优点与活性聚合物基质提供这些电磁性能的远程调谐的能力。压电和光活性聚合物将被用来耦合平面结构中的磁性纳米线。 在压电矩阵的情况下，施加在整个设备的电场？S平面将决定其平面尺寸的变化，这将改变磁性纳米线之间的平均距离。对于光活性聚合物，除了平均线间距离的变化之外，当聚合物膜的平面性在光学刺激的作用下改变时，可以触发线的角纹理的变化。磁性纳米线和刺激响应基质之间的这两种耦合机制都将影响复合材料的频率响应，因为铁磁共振频率强烈依赖于线间相互作用和线的取向。 从该项目中获得的发现将有助于对纳米级物理现象，特别是纳米磁性的基本理解，为介观磁性结构的动态特性提供见解。社会的直接利益来自于拟议活动对射频和微波技术的巨大影响。此外，该项目将为物理，化学和纳米材料科学的研究生和本科生提供重要的培训。 学生将参与该计划的各个方面，在这些材料的加工和表征方面获得重要经验。 此外，该计划将有助于扩大路易斯安那州的纳米技术教育，让本科生，特别是少数民族，了解最新的研究进展。

The objective of this research is to develop novel frequency agile reciprocal (tunable filters) and non-reciprocal (isolator and circulator) microwave devices based on stimuli-responsive magnetic nanowires composites. In the modern world when wireless connectivity guarantees to provide voice, video and data access to ?everyone, anywhere, and anytime? there is a constant need for remotely tunable microwave devices. The proposed research will integrate fabrication of magnetic nanowires, frequency agile microwave device design, characterization and modeling.Intellectual Merit. For more than half a century the ferrites were the ?workhorse? of the microwave devices, especially for nonreciprocal applications. The main advantage of ferrites is the fact that they provide an extremely high electrical resistivity with reasonable good magnetic properties, which is very important at high frequencies view the eddy?current loss. However, their average magnetic properties impacts negatively the size and weight of ferrite based microwave devices. The stimuli-responsive magnetic nanowires composites will combine the advantages provided by superior electromagnetic properties of magnetic nanowires with the ability of the active polymer matrix to provide a remote tuning of these electromagnetic properties. Piezoelectric and light active polymers will be used to couple magnetic nanowires in planar structures. In the case of a piezoelectric matrix, an electric field applied across the device?s plane will determine a variation in its planar dimensions which will change the average distance between the magnetic nanowires. For light active polymers, besides a variation of the average interwire distance, a change in the angular texture of the wires can be triggered as the planarity of the polymer film changes under the action of an optical stimulus. Both of these coupling mechanisms between magnetic nanowires and stimuli responsive matrices will affect the frequency response of the composite material, as the ferromagnetic resonance frequency is strongly dependent on interwire interactions and orientation of the wires.Broader Impact. The findings gained from this project will contribute to the basic understanding of the nanoscale physical phenomena, specifically nanomagnetism, providing insights into the dynamic properties of mesoscopic magnetic structures. The immediate benefit for the society comes from the big impact of the proposed activity on rf and microwave technologies. Also, this project will provide important training for graduate and undergraduate students in Physics, Chemistry and Nanomaterials Science. Students will be involved in all aspects of this program gaining important experience in processing and characterization of these materials. Further, this program will serve to expand nanotechnology education in Louisiana by exposing undergraduates students, especially minorities, to the latest research developments.