This research is directed at the development of a spin injection technique utilizing a new class of materials, diluted magnetic dielectrics (DMD). DMD are both ferromagnetic at room temperature and yet insulating, the latter in contrast with diluted magnetic semiconductors (DMS). This proposal will make use of our recent observation that the presence of carriers is not required for ferromagnetism in wide band gap oxides such as TiO2 or ZnO doped with transition metal ions. Spin injection will be achieved through spin filtering in a magnetic tunnel barrier. This research will explore both fundamental material and device issues of DMD materials and their practical application. Magnetic, structural, morphological and dielectric properties of DMD thin films will be optimized in application to spin filtering barriers. For this purpose, scaling laws will be found for the physical properties with the film thickness decreasing to ~2 nanometers, an estimated optimum barrier thickness. This will also provide a new insight into the mechanisms of ferromagnetism in DMD materials. The final objective of this research is to investigate both spin filtering and electrical spin injection via DMD spin filter tunnel barriers, and to demonstrate prototype device structures using these effects. The demonstration device structures will be grown editorially using sputtering techniques and investigated by a variety of advanced characterization, and measurement methods. Broadly, this research will add momentum to the development of the field of semiconductor spin electronics by providing a realistic route for the development of practically useful devices. Effective injection of magnetically polarized current carriers into semiconductor structures, especially at room temperatures, and the demonstration of a practical device are the goals.
The proposal will also have broad impact on teaching, educational and outreach activities at UW. Specifically, it will have direct bearing on both graduate (Magnetic materials, Bonding and crystallography) and undergraduate (Nanoscience and nanotechnology) courses that the PI teaches at UW. The latter is taught in a cooperative learning mode with supervised involvement of the graduate students in the education of undergraduates. The PI and his research group, especially the graduate and undergraduate students, are actively involved in outreach activities through the annual UW, College of Engineering open house that is attended by more than 4000 students from local schools. We developed an extensive, interactive and very popular exhibit on magnetism and spin-electronics for the first time last year and this will be refined and enlarged in the coming years. The project will also include collaborative work with the Tokyo Institute of Technology with emphasis on graduate student training and education. The PI is also committed to enhancing the diversity of the graduate student participation in his research program; he is a founding member of the UW Graduate School faculty committee on Recruitment from Minority Serving Institutions. The UW also has a wide range of acclaimed programs to encourage diversity in research and teaching. The PI will continue to actively work with these organizations, specifically the Center for Instructional Research and Development (CIDR), Center for Engineering Learning and Teaching (CELT), Minority Science and Engineering Program (MSEP) and Women in Science and Engineering (WiSE) to increase the participation of women and people of diverse backgrounds in all his teaching and research activities on the UW campus.
