Spin precession in freely-suspended graphene nonlocal spin valves

I. NEUMANN; J. VAN DE VONDEL; G. BRIDOUX; M. V. COSTACHE; S. O. VALENZUELA

Granada

Conferencia; Granada´12-Graphene Nanoscience: from Dirac Physics to Applications; 2012

We achieve spin injection and detection in freely-suspended graphene using cobalt electrodesand a nonlocal spin-valve geometry. The devices are fabricated with a single electron-beamresistprocess that minimizes both the fabrication steps and the number of (aggressive)chemicals used, greatly reducing contamination and increasing the yield of high-quality,mechanically stable devices. As-grown devices can present mobilities exceeding 104 cm2 V-1s-1 at room temperature and, because the contacts deposited on graphene are only exposed toacetone and isopropanol, the method is compatible with almost any contacting material. Westudy spin accumulation and spin precession in our nonlocal spin valves. Fitting of Hanle spinprecession data in bilayer and multilayer graphene yields a spin relaxation time of ~ 125-250ps and a spin diffusion length of 1.7-1.9 μm at room temperature.