Spin communication over 30 µm long channels of chemical vapor deposited graphene on SiO2

We demonstrate a high-yield fabrication of non-local spin valve devices with room-temperature spin lifetimes of up to 3 ns and spin relaxation lengths as long as 9 µm in platinum-based chemical vapor deposition (Pt-CVD) synthesized single-layer graphene on SiO2/Si substrates. The spin-lifetime systematically presents a marked minimum at the charge neutrality point, as typically observed in pristine exfoliated graphene. However, by studying the carrier density dependence beyond n ~ 5 × 1012 cm−2, via electrostatic gating, it is found that the spin lifetime reaches a maximum and then starts decreasing, a behavior that is reminiscent of that predicted when the spin-relaxation is driven by spin–orbit interaction. The spin lifetimes and relaxation lengths compare well with state-of-the-art results using exfoliated graphene on SiO2/Si, being a factor two-to-three larger than the best values reported at room temperature using the same substrate. As a result, the spin signal can be readily measured across 30 µm long graphene channels. These observations indicate that Pt-CVD graphene is a promising material for large-scale spin-based logic-in-memory applications.This research was partially supported by the European Union’s Horizon 2020 research and innovation programme, Graphene Flagship CORE 2, under grant agreement No. 785219, by the Spanish Ministry of Economy and Competitiveness, MINECO (under Contracts No. MAT2013-46785-P, No. MAT2016-75952-R, No. MAT2015-68307-P and Severo Ochoa No. SEV- 2017-0706), and by the CERCA Programme and the Secretariat for Universities and Research, Knowledge Department of the Generalitat de Catalunya, 2017 SGR 827. ZMG acknowledges support from MINECO FPI fellowship under Contract No. BES-2014-069925 and MT from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodoswa-Curie grant agreement Nº 665919.Peer reviewe