Spin communication over 30 $\mu$m long channels of chemical vapor deposited graphene on SiO$_2$

TL;DR

This study demonstrates high-yield fabrication of graphene spintronic devices with long spin lifetimes and relaxation lengths, showing potential for large-scale spin-based memory applications.

Contribution

It reports the first large-scale spin communication over 30 μm channels in CVD-grown graphene with record spin lifetimes at room temperature.

Findings

Spin lifetime up to 3 ns at room temperature.

Spin relaxation length as long as 9 μm.

Effective spin communication over 30 μm channels.

Abstract

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 $\mu$m in platinum-based chemical vapor deposition (Pt-CVD) synthesized single-layer graphene on SiO$_2$/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 x 10$^{12}$ 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 SiO$_2$/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 $\mu$m long graphene channels. These observations indicate that Pt-CVD graphene is a promising material for large-scale spin-based logic-in-memory applications.