Suppression of contact-induced spin dephasing in graphene/MgO/Co spin-valve devices by successive oxygen treatments
arXiv:1408.1427 · doi:10.1103/PhysRevB.90.165403
Abstract
By successive oxygen treatments of graphene non-local spin-valve devices we achieve a gradual increase of the contact resistance area products () of Co/MgO spin injection and detection electrodes and a transition from linear to non-linear characteristics in the respective differential dV-dI-curves. With this manipulation of the contacts both spin lifetime and amplitude of the spin signal can significantly be increased by a factor of seven in the same device. This demonstrates that contact-induced spin dephasing is the bottleneck for spin transport in graphene devices with small values. With increasing values, we furthermore observe the appearance of a second charge neutrality point (CNP) in gate dependent resistance measurements. Simultaneously, we observe a decrease of the gate voltage separation between the two CNPs. The strong enhancement of the spin transport properties as well as the changes in charge transport are explained by a gradual suppression of a Co/graphene interaction by improving the oxide barrier during oxygen treatment.
12 pages, 10 figures
References in corpus (19)
- Electric Field Effect in Atomically Thin Carbon Films
- Doping graphene with metal contacts
- Atomic Structure of Graphene on SiO2
- Tunneling Spin Injection into Single Layer Graphene (Supplementary Information)
- Tunneling Spin Injection into Single Layer Graphene
- Magnetic Moment Formation in Graphene Detected by Scattering of Pure Spin Currents
- Controlling spin relaxation in hexagonal BN-encapsulated graphene with a transverse electric field
- Spin transport in high quality suspended graphene devices
- Long spin relaxation times in wafer scale epitaxial graphene on SiC(0001)
- Electrically Controlled Adsorption of Oxygen in Bilayer Graphene Devices
- Contact induced spin relaxation in Hanle spin precession measurements
- Inter-Layer Screening Length to Electric Field in Thin Graphite Film
- Charge-density depinning at metal contacts of graphene field-effect transistors
- Enhancement of spin relaxation time in hydrogenated graphene spin valve devices
- Spin Relaxation in Single Layer Graphene with Tunable Mobility
- Field effect doping of graphene in metal|dielectric|graphene heterostructures: a model based upon first-principles calculations
- Annealing-induced magnetic moments detected by spin precession measurements in epitaxial graphene on SiC
- Transport in Graphene Tunnel Junctions
- Unipolar transport in bilayer graphene controlled by multiple p-n interfaces