spin transport signal ( W )

1. Hydrogen Turns Graphene MagneticRoland K. Kawakami, University of California-Riverside, DMR 1007057 Theorists predicted that hydrogen adsorbates and other point defects could turn graphene magnetic, but the experimental situation has been unclear. Using pure spin currents in graphene as a probe, Kawakami demonstrated the existence of magnetism in graphene and also showed that hydrogen-induced magnetic moments can be used to control spin transport signals. At low magnetic fields, the magnetic moments scatter the spin current to generate a small spin signal. With a high magnetic field, this scattering is turned off to yield a large spin signal. This transistor-like action forms the basis of a “magnetic field effect transistor” (MFET), a new building block for spintronics. Ferromagnetic spin injector Ferromagnetic spin detector H-doped graphene M M H H H spin current Spin scattering OFF Spin scattering ON Parallel spin transport signal (W) Antiparallel magnetic field (mT)

2. Undergraduates Design and Build MBE systemRoland K. Kawakami, University of California-Riverside, DMR 1007057 A team of undergraduates is performing PhD-level research as they design and build a molecular beam epitaxy (MBE) system capable of atom-by-atom deposition of thin film nanostructures. Students receive hands-on experience with ultrahigh vacuum hardware, computer aided design, electronic circuit building, and materials science. Undergraduates will use the MBE system for synthesizing single-crystal graphene*, ferromagnet/silicon-germanium hybrid structures, and epitaxial oxides. This experience helps prepare students for graduate school and industrial jobs. *The graphene portion has been funded by this grant. (left to right):Alexander Speirs, Carlos Gallardo, Igor Pinchuk, Andrew Nguyen, George Christensen Computer Aided Design Electronic Circuit Building