Absence of hyperfine effects in $^{13}$C-graphene spin valve devices
| Autor: | M. Wojtaszek, Michael Hilke, Ivan J. Vera-Marun, Eric Whiteway, van Bart Wees |
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| Přispěvatelé: | Zernike Institute for Advanced Materials, Physics of Nanodevices, Surfaces and Thin Films |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Physics
Condensed matter physics Magnetic moment Condensed Matter - Mesoscale and Nanoscale Physics Graphene Dephasing Spin valve FOS: Physical sciences Condensed Matter Physics Electronic Optical and Magnetic Materials Magnetic field law.invention law Nuclear magnetic moment Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Physics::Atomic Physics Atomic physics Spin (physics) Hyperfine structure |
| Zdroj: | Physical Review B, 89(3). AMER PHYSICAL SOC |
| ISSN: | 1098-0121 |
| Popis: | The carbon isotope $^{13}$C, in contrast to $^{12}$C, possesses a nuclear magnetic moment and can induce electron spin dephasing in graphene. This effect is usually neglected due to the low abundance of $^{13}$C in natural carbon allotropes ($\sim$1 %). Chemical vapor deposition (CVD) allows for artificial synthesis of graphene solely from a $^{13}$C precursor, potentially amplifying the influence of the nuclear magnetic moments. In this work we study the effect of hyperfine interactions in pure $^{13}$C-graphene on its spin transport properties. Using Hanle precession measurements we determine the spin relaxation time and observe a weak increase of $\tau_{s}$ with doping and a weak change of $\tau_{s}$ with temperature, as in natural graphene. For comparison we study spin transport in pure $^{12}$C-graphene, also synthesized by CVD, and observe similar spin relaxation properties. As the signatures of hyperfine effects can be better resolved in oblique spin-valve and Hanle configurations, we use finite-element modeling to emulate oblique signals in the presence of a hyperfine magnetic field for typical graphene properties. Unlike in the case of GaAs, hyperfine interactions with $^{13}$C nuclei influence electron spin transport only very weakly, even for a fully polarized nuclear system. Also, in the measurements of the oblique spin-valve and Hanle effects no hyperfine features could be resolved. This work experimentally confirms the weak character of hyperfine interactions and the negligible role of $^{13}$C atoms in the spin dephasing processes in graphene. Comment: 11 pages, 9 figures |
| Databáze: | OpenAIRE |
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