TY  - JOUR
AU  - Drögeler, Marc
AU  - Franzen, Christopher
AU  - Volmer, Frank
AU  - Pohlmann, Tobias
AU  - Banszerus, Luca
AU  - Wolter, Maik
AU  - Watanabe, Kenji
AU  - Taniguchi, Takashi
AU  - Stampfer, Christoph
AU  - Beschoten, Bernd
TI  - Spin Lifetimes Exceeding 12 ns in Graphene Nonlocal Spin Valve Devices
JO  - Nano letters
VL  - 16
IS  - 6
SN  - 1530-6992
CY  - Washington, DC
PB  - ACS Publ.
M1  - FZJ-2017-02575
SP  - 3533 - 3539
PY  - 2016
AB  - We show spin lifetimes of 12.6 ns and spin diffusion lengths as long as 30.5 μm in single layer graphene nonlocal spin transport devices at room temperature. This is accomplished by the fabrication of Co/MgO-electrodes on a Si/SiO2 substrate and the subsequent dry transfer of a graphene-hBN-stack on top of this electrode structure where a large hBN flake is needed in order to diminish the ingress of solvents along the hBN-to-substrate interface. Interestingly, long spin lifetimes are observed despite the fact that both conductive scanning force microscopy and contact resistance measurements reveal the existence of conducting pinholes throughout the MgO spin injection/detection barriers. Compared to previous devices, we observe an enhancement of the spin lifetime in single layer graphene by a factor of 6. We demonstrate that the spin lifetime does not depend on the contact resistance area products when comparing all bottom-up devices indicating that spin absorption at the contacts is not the predominant source for spin dephasing.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000377642700018
C6  - pmid:27210240
DO  - DOI:10.1021/acs.nanolett.6b00497
UR  - https://juser.fz-juelich.de/record/828683
ER  -