Reflection-based Spintronics

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The objective of this research is to engineer thin film spintronic devices based on a dynamic magnetic proximity effect. A non-zero spin-polarization will be induced in a non-magnetic material by reflection of conduction electrons off the interface of an insulating magnetic material. The approach is to fabricate non-magnetic-conductor/magnetic-insulator structures completely in situ, then probe the resulting spin-polarized current via three complementary techniques: tunneling magnetoresistance, tunneling spin polarization, and x-ray magnetic circular dichroism. Trilayer device structures with independently addressable magnetic layers will also be explored.Intellectual Merit: This project may spearhead a paradigm shift for all-electrical spintronics. Present efforts focus on injecting spins from ferromagnets into non-magnetic materials. However, spin-injection has crippled progress, particularly for semiconductor-based devices. The proposed devices induce a spin-polarization in a non-magnetic conduction channel by reflection off an insulating magnetic gate, thereby obviating the difficulties of injection. This project will develop the building blocks for a series of more complex device architectures able to deliver electrically tunable spin-polarized currents.Broader Impacts: This transformational research may ease the integration of spintronics with existing back-end semiconductor processing, thereby substantially reducing barriers to commercial spintronics. This program integrates teaching and multidisciplinary training of undergraduate and graduate students, including those from under-represented groups, by unifying physics, engineering, and materials concepts, and by developing hands-on spintronics experiments for high school and undergraduate laboratories. This work enhances infrastructure via a new collaboration between the University of South Florida and the Advanced Light Source.