  We have fabricated graphene spin-valve devices utilizing scalable materials
made from chemical vapor deposition (CVD). Both the spin-transporting graphene
and the tunnel barrier material are CVD-grown. The tunnel barrier is realized
by h-BN, used either as a monolayer or bilayer and placed over the graphene.
Spin transport experiments were performed using ferromagnetic contacts
deposited onto the barrier. We find that spin injection is still greatly
suppressed in devices with a monolayer tunneling barrier due to resistance
mismatch. This is, however, not the case for devices with bilayer barriers. For
those devices, a spin relaxation time of 260 ps intrinsic to the CVD graphene
material is deduced. This time scale is comparable to those reported for
exfoliated graphene, suggesting that this CVD approach is promising for
spintronic applications which require scalable materials.
