Room Temperature Spin Transport in Sub-50 nm Bilayer Graphene Nanoribbons

The graphene nanoribbons (GNRs) are one-dimensional strips of graphene, holding great promise for spintronic devices due to their distinctive edge- and quantum effect-related electronic and magnetic properties. However, spin current transport has not been demonstrated in spintronic devices based on GNRs with sub-50 nm feature widths, posing a significant obstacle to GNR spintronics. In this study, we present the observation of room temperature spin transport in bilayer GNR arrays with widths ranging from ∼15 to ∼35 nm and lengths up to ∼150 nm. Our experimental approach involved a nonlocal spin valve geometry, utilizing four-terminal contact geometries with two inner ferromagnetic cobalt electrodes to inject and detect the pure spin current diffuse across the bilayer GNRs. Clear gate-tunable spin valve signals were detected in the nonlocal bilayer GNR spin valve device, persisting at room temperature. Furthermore, the Hanle spin precession experiment has also been conducted, confirming robust spin current transport in sub-50 nm GNR spin valve devices.