Contact-Induced Spin Relaxation in Graphene Nonlocal Spin Valves

Gordon Stecklein; Paul A. Crowell; Jing Li; Yoska Anugrah; Qun Su; Steven J. Koester

doi:10.1103/PhysRevApplied.6.054015

Contact-Induced Spin Relaxation in Graphene Nonlocal Spin Valves

Gordon Stecklein, Paul A. Crowell, Jing Li, Yoska Anugrah, Qun Su, Steven J. Koester

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

We report on a systematic study of contact-induced spin relaxation in gated graphene nonlocal spin valves. We demonstrate the enhancement of the nonlocal magnetoresistance (ΔRNL) as the Co/AlOx/graphene interface resistance increases relative to the graphene spin resistance. We measure Hanle precession at many gate voltages on 14 separate spin-valve devices fabricated from graphene grown by chemical vapor deposition (CVD). These measurements are compared by normalizing ΔRNL to the ideal limit of large contact resistance, and the result is shown to be consistent with isotropic contact-induced spin relaxation caused by spin current flowing from the graphene into the Co contacts. After accounting for this source of spin relaxation, we extract spin lifetimes of up to 600 ps in CVD graphene with a gate-voltage dependence which can be described by a combination of both Elliott-Yafet and D'yakonov-Perel' spin-relaxation mechanisms.

Original language	English (US)
Article number	054015
Journal	Physical Review Applied
Volume	6
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevApplied.6.054015
State	Published - Nov 28 2016

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation under Grant No.ECCS-1124831, the Nanoelectronics Research Initiative of the Semiconductor Research Corporation (SRC), and C-SPIN, a SRC STARnet center sponsored by MARCO and DARPA. Portions of this work were carried out at the College of Science and Engineering Characterization Facility, University of Minnesota (UMN), which has received capital equipment funding from the NSF through the UMN MRSEC program under Grant No.DMR-1420013. Device fabrication was carried out in the Minnesota Nano Center, which receives partial support from the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI).

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© 2016 American Physical Society.

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title = "Contact-Induced Spin Relaxation in Graphene Nonlocal Spin Valves",

abstract = "We report on a systematic study of contact-induced spin relaxation in gated graphene nonlocal spin valves. We demonstrate the enhancement of the nonlocal magnetoresistance (ΔRNL) as the Co/AlOx/graphene interface resistance increases relative to the graphene spin resistance. We measure Hanle precession at many gate voltages on 14 separate spin-valve devices fabricated from graphene grown by chemical vapor deposition (CVD). These measurements are compared by normalizing ΔRNL to the ideal limit of large contact resistance, and the result is shown to be consistent with isotropic contact-induced spin relaxation caused by spin current flowing from the graphene into the Co contacts. After accounting for this source of spin relaxation, we extract spin lifetimes of up to 600 ps in CVD graphene with a gate-voltage dependence which can be described by a combination of both Elliott-Yafet and D'yakonov-Perel' spin-relaxation mechanisms.",

author = "Gordon Stecklein and Crowell, {Paul A.} and Jing Li and Yoska Anugrah and Qun Su and Koester, {Steven J.}",

note = "Funding Information: This work was supported by the National Science Foundation under Grant No.ECCS-1124831, the Nanoelectronics Research Initiative of the Semiconductor Research Corporation (SRC), and C-SPIN, a SRC STARnet center sponsored by MARCO and DARPA. Portions of this work were carried out at the College of Science and Engineering Characterization Facility, University of Minnesota (UMN), which has received capital equipment funding from the NSF through the UMN MRSEC program under Grant No.DMR-1420013. Device fabrication was carried out in the Minnesota Nano Center, which receives partial support from the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI). Publisher Copyright: {\textcopyright} 2016 American Physical Society.",

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AU - Crowell, Paul A.

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AU - Su, Qun

AU - Koester, Steven J.

N1 - Funding Information: This work was supported by the National Science Foundation under Grant No.ECCS-1124831, the Nanoelectronics Research Initiative of the Semiconductor Research Corporation (SRC), and C-SPIN, a SRC STARnet center sponsored by MARCO and DARPA. Portions of this work were carried out at the College of Science and Engineering Characterization Facility, University of Minnesota (UMN), which has received capital equipment funding from the NSF through the UMN MRSEC program under Grant No.DMR-1420013. Device fabrication was carried out in the Minnesota Nano Center, which receives partial support from the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI). Publisher Copyright: © 2016 American Physical Society.

PY - 2016/11/28

Y1 - 2016/11/28

N2 - We report on a systematic study of contact-induced spin relaxation in gated graphene nonlocal spin valves. We demonstrate the enhancement of the nonlocal magnetoresistance (ΔRNL) as the Co/AlOx/graphene interface resistance increases relative to the graphene spin resistance. We measure Hanle precession at many gate voltages on 14 separate spin-valve devices fabricated from graphene grown by chemical vapor deposition (CVD). These measurements are compared by normalizing ΔRNL to the ideal limit of large contact resistance, and the result is shown to be consistent with isotropic contact-induced spin relaxation caused by spin current flowing from the graphene into the Co contacts. After accounting for this source of spin relaxation, we extract spin lifetimes of up to 600 ps in CVD graphene with a gate-voltage dependence which can be described by a combination of both Elliott-Yafet and D'yakonov-Perel' spin-relaxation mechanisms.

AB - We report on a systematic study of contact-induced spin relaxation in gated graphene nonlocal spin valves. We demonstrate the enhancement of the nonlocal magnetoresistance (ΔRNL) as the Co/AlOx/graphene interface resistance increases relative to the graphene spin resistance. We measure Hanle precession at many gate voltages on 14 separate spin-valve devices fabricated from graphene grown by chemical vapor deposition (CVD). These measurements are compared by normalizing ΔRNL to the ideal limit of large contact resistance, and the result is shown to be consistent with isotropic contact-induced spin relaxation caused by spin current flowing from the graphene into the Co contacts. After accounting for this source of spin relaxation, we extract spin lifetimes of up to 600 ps in CVD graphene with a gate-voltage dependence which can be described by a combination of both Elliott-Yafet and D'yakonov-Perel' spin-relaxation mechanisms.

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Contact-Induced Spin Relaxation in Graphene Nonlocal Spin Valves

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MRSEC IRG-1: Electrostatic Control of Materials

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Contact-Induced Spin Relaxation in Graphene Nonlocal Spin Valves

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Bibliographical note

MRSEC Support

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MRSEC IRG-1: Electrostatic Control of Materials

University of Minnesota MRSEC (DMR-1420013)

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