Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 43: Joint Session "Graphen: Spin Transport" (jointly with DS, DY, HL, O, TT)

MA 43.2: Invited Talk

Thursday, March 29, 2012, 15:30–16:00, H 1012

Long spin relaxation times in epitaxial graphene on SiC(0001) — •Thomas Maassen¹, Jan Jasper van den Berg¹, Natasja IJbema¹, Felix Fromm², Thomas Seyller², Rositsa Yakimova³, and Bart Jan van Wees¹ — ¹Zernike Institute for Advanced Materials, University of Groningen, The Netherlands — ²Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, Germany — ³Department of Physics, Chemistry and Biology (IFM), Linköping University, Sweden

Spin transport in graphene draws great interest because of recent promising measurements at room temperature (RT). At the same time the limiting factor for spin relaxation seems to be the substrate. By replacing the commonly used SiO₂ substrate we aim to observe improved spin transport. We developed an easy process to prepare lateral spin-valve devices on epitaxial grown monolayer graphene on SiC(0001), that enables us to upscale the production to wafer size. We examine the spin transport properties of this material by performing nonlocal spin-valve and Hanle spin precession measurements. We observe the longest spin relaxation time τ_S in single layer graphene at RT (1.5 ns) and T=4.2 K (2.3 ns), while the spin diffusion coefficient is strongly reduced by nearly 2 orders of magnitude. The increase in τ_S is probably related to the changed substrate, while the small value for D_S is until now unexplained. Nevertheless, the high values for τ_S, combined with the easy production method on a large scale, clear the way for graphene based spintronic devices and applications in the future.