24 m length spin relaxation length in boron nitride encapsulated bilayer graphene

الأصل · EN

We have performed spin and charge transport measurements in dual gated high mobility bilayer graphene encapsulated in hexagonal boron nitride. Our results show spin relaxation lengths λₛ up to 13 m at room temperature with relaxation times τₛ of 2.5 ns. At 4 K, the diffusion coefficient rises up to 0.52 m²/s, a value 5 times higher than the best achieved for graphene spin valves up to date. As a consequence, λₛ rises up to 24 m with τₛ as high as 2.9 ns. We characterized 3 different samples and observed that the spin relaxation times increase with the device length. We explain our results using a model that accounts for the spin relaxation induced by the non-encapsulated outer regions.