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Abstract
Graphene lateral spin valves (LSVs) are promising devices for future memory and magnetic field sensing applications. In this article, we study the dependence of the nonlocal spin resistance,RNL, and the baseline resistance, RBS, as a function of the graphene channel width, W. The scaling trend is quantitatively assessed by using graphene deposited by chemical vapor deposition, which provides a large number of devices with consistent performance.AsWis scaled from 10 to 0.5μm, the change in RNL matches the theory of contact-induced spin relaxation with a current spin polarization of 3%-5% and a spin diffusion length of λs = 1.5-2.5 ìm. We also observe a systematic and dramatic decrease in RBS, which we attribute to the reduction in charge current spreading. However, we find in the narrowest devices that a small RBS remains that arises due to thermoelectric effects, and this trend is confirmed using gate voltage-A nd charge current-dependentanalyses. Finally, we introduce a nonideality factor, m = |RBS/RNL|, as a figure of merit to describe the suppression of the baseline relative to the spin signal. In an LSV with L = 1.5 μm, W = 0.5 μm, and n-type conduction, the nonideality factor is as low asm = 0.0252± 0.0202 at room temperature showing that nearly ideal bipolar and symmetric spin signals can be achieved in graphene LSVs.
Original language | English (US) |
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Article number | 8871329 |
Pages (from-to) | 5003-5010 |
Number of pages | 8 |
Journal | IEEE Transactions on Electron Devices |
Volume | 66 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2019 |
Bibliographical note
Funding Information:The authors would like to thank J. D. Watts for fruitful discussions. This work also utilized the University of Minnesota Characterization Facility which receives capital equipment support from the National Science Foundation (NSF) through the University of Minnesota MRSEC under Award DMR-1420013. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the NSF through the National Nanotechnology Coordinated Infrastructure under Award ECCS-1542202.
Publisher Copyright:
© 2019 IEEE.
Keywords
- Ferromagnet
- graphene
- lateral spin valve (LSV)
How much support was provided by MRSEC?
- Shared
Reporting period for MRSEC
- Period 6
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MRSEC IRG-1: Electrostatic Control of Materials
Leighton, C., Birol, T., Fernandes, R. M., Frisbie, D., Goldman, A. M., Greven, M., Jalan, B., Koester, S. J., He, T., Jeong, J. S., Koirala, S., Paul, A., Thoutam, L. R. & Yu, G.
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Project: Research project
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