Microwave Losses and Interactions in Patterned Magnetic Nanostructures

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The objective of this research is to provide a deeper understanding of the mechanism of high frequency losses in nanoscale magnetic systems such as arrays of lithographically-patterned nanostructures. The approach is to use ferromagnetic resonance (FMR) and static magnetic measurements to investigate the coercivity, switching field distribution, and resonance linewidth, the relationship between these quantities, and the contribution from interactions between the nanomagnets to these properties. Within small magnetic elements, spin waves and magnetostatic modes are excited, and the statistical distribution of properties of the elements make such systems lossy over a band of excitations. Sensitive FMR and broadband measurements will reveal these modes and provide loss data. Intellectual MeritThis work is important because small magnetic particles play a critical role in applications such as future extreme high density storage, sensor arrays, and magnetic random access memories. While the size of the magnetic elements is decreasing, the speed of operation is increasing. As a result, understanding the problem of high frequency performance and losses becomes essential. The broader impacts of this proposal include the training of graduate and undergraduate students; the incorporation of research knowledge into classes taught in both MIT and GWU; and the demonstration of the relation between research, discovery, its application and societal benefits by educational outreach activity to promote science and technology among non-science majors and female high school students. This will be carried out through talks and demonstrations of technologically critical devices such as disk drives, transistors or optical fibers, presented in high schools.