Spin splitting in graphene is required to develop graphene-based multifunctional spintronic devices with low dissipation and long-distance spin transport. Magnetic proximity effects are a promising route to realize exchange splitting in the material, which is otherwise intrinsically non-spin-polarized. Here, we show that monolayer graphene can be magnetized by coupling to an antiferromagnetic thin film of chromium selenide, resulting in an exchange splitting energy as high as 134 meV at 2 K. This exchange splitting is shown through shifts in the quantum Hall plateau and quantum oscillations in the graphene, and its energy can be modulated through field cooling, with the exchange splitting energy increasing with positive field cooling and decreasing with negative field cooling. Our experimental demonstration of magnetism in graphene at low temperatures is supported by measurements of resistivity dependence on temperature and magneto-optic Kerr measurements.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the plots within this paper and other findings of this study are available in figshare with the identifier 10.6084/m9.figshare.12331154 (https://figshare.com/articles/dataset/source-data-for-Gr-CrSe-paper_xlsx/12331154).
Han, W., Kawakami, R. K., Gmitra, M. & Fabian, J. Graphene spintronics. Nat. Nanotechnol. 9, 794–807 (2014).
Roche, S. & Valenzuela, S. O. Graphene spintronics: puzzling controversies and challenges for spin manipulation. J. Phys. D 47, 094011 (2014).
Hill, E. W., Geim, A. K., Novoselov, K., Schedin, F. & Blake, P. Graphene spin valve devices. IEEE Trans. Magn. 42, 2694–2696 (2006).
Cho, S., Chen, Y.-F. & Fuhrer, M. S. Gate-tunable graphene spin valve. Appl. Phys. Lett. 91, 123105 (2007).
Ingla-Aynés, J., Meijerink, R. J. & Wees, B. J. Eighty-eight percent directional guiding of spin currents with 90-μm relaxation length in bilayer graphene using carrier drift. Nano Lett. 16, 4825–4830 (2016).
Drogeler, M. et al. Spin lifetimes exceeding 12 ns in graphene nonlocal spin valve devices. Nano Lett. 16, 3533–3539 (2016).
Tombros, N., Jozsa, C., Popinciuc, M., Jonkman, H. T. & Van Wees, B. J. Electronic spin transport and spin precession in single graphene layers at room temperature. Nature 448, 571–574 (2007).
Stepanov, P. et al. Long-distance spin transport through a graphene quantum Hall antiferromagnet. Nat. Phys. 14, 907–911 (2018).
Haugen, H., Huertas-Hernando, D. & Brataas, A. Spin transport in proximity-induced ferromagnetic graphene. Phys. Rev. B 77, 115406 (2008).
Yang, H.-X. et al. Proximity effects induced in graphene by magnetic insulators: first-principles calculations on spin filtering and exchange-splitting gaps. Phys. Rev. Lett. 110, 046603 (2013).
Su, S., Barlas, Y., Li, J., Shi, J. & Lake, R. K. Effect of intervalley interaction on band topology of commensurate graphene/EuO heterostructures. Phys. Rev. B 95, 075418 (2017).
Gan, L.-Y., Zhang, Q., Guo, C.-S., Schwingenschlögl, U. & Zhao, Y. Two-dimensional MnO2/graphene interface: half-metallicity and quantum anomalous Hall state. J. Phys. Chem. C 120, 2119–2125 (2016).
Hallal, A., Ibrahim, F., Yang, H., Roche, S. & Chshiev, M. Tailoring magnetic insulator proximity effects in graphene: first-principles calculations. 2D Mater. 4, 025074 (2017).
Wei, P. et al. Strong interfacial exchange field in the graphene/EuS heterostructure. Nat. Mater. 15, 711–716 (2016).
Martí, X., Fina, I. & Jungwirth, T. Prospect for antiferromagnetic spintronics. IEEE Trans. Magn. 51, 1–4 (2015).
Marti, X. et al. Room-temperature antiferromagnetic memory resistor. Nat. Mater. 13, 367–374 (2014).
Jungwirth, T., Marti, X., Wadley, P. & Wunderlich, J. Antiferromagnetic spintronics. Nat. Nanotechnol. 11, 231–241 (2016).
Moriyama, T. et al. Sequential write–read operations in FeRh antiferromagnetic memory. Appl. Phys. Lett. 107, 122403 (2015).
Zhou, B. et al. Gate-tuned charge-doping and magnetism in graphene/α-RuCl3 heterostructures. Preprint at https://arxiv.org/pdf/1811.04838.pdf (2018).
Qiao, Z. et al. Quantum anomalous Hall effect in graphene proximity coupled to an antiferromagnetic insulator. Phys. Rev. Lett. 112, 116404 (2014).
Polesya, S., Mankovsky, S., Benea, D., Ebert, H. & Bensch, W. Finite-temperature magnetism of CrTe and CrSe. J. Phys. Condens. Matter 22, 156002 (2010).
Ivanova, V., Abdinov, D. S. & Aliev, G. On some characteristics of chromium selenides. Phys. Status Solidi B 24, K145–K147 (1967).
Corliss, L., Elliott, N., Hastings, J. & Sass, R. Magnetic structure of chromium selenide. Phys. Rev. 122, 1402 (1961).
Makovetskii, G. & Shakhlevich, G. Magnetic properties of the CrS1 − xSex system. Phys. Status Solidi. A 47, 219–222 (1978).
Katsuyama, S., Ueda, Y. & Kosuge, K. Phase diagram and order-disorder transition of vacancies in the Cr1bSe and Fe1bSe systems. Mater. Res. Bull. 25, 913–922 (1990).
Yan, J. et al. Anomalous Hall effect in two-dimensional non-collinear antiferromagnetic semiconductor Cr0.68Se. Appl. Phys. Lett. 111, 022401 (2017).
Hayashi, A. et al. Cation distribution in (M′, M)3Se4: II. (V,Ti)3Se4 and (Cr,V)3Se4. J. Solid State Chem. 71, 237–243 (1987).
Graf, D. et al. Spatially resolved Raman spectroscopy of single-and few-layer graphene. Nano Lett. 7, 238–242 (2007).
Ferrari, A. C. et al. Raman spectrum of graphene and graphene layers. Phys. Rev. Lett. 97, 187401 (2006).
Zhu, W., Seve, L., Sears, R., Sinkovic, B. & Parkin, S. Field cooling induced changes in the antiferromagnetic structure of NiO films. Phys. Rev. Lett. 86, 5389 (2001).
Ambrose, T. & Chien, C. Dependence of exchange field and coercivity on cooling field in NiFe/CoO bilayers. J. Appl. Phys. 83, 7222–7224 (1998).
Koon, N. Calculations of exchange bias in thin films with ferromagnetic/antiferromagnetic interfaces. Phys. Rev. Lett. 78, 4865 (1997).
Hoffmann, A. Symmetry driven irreversibilities at ferromagnetic–antiferromagnetic interfaces. Phys. Rev. Lett. 93, 097203 (2004).
Kriegner, D. et al. Multiple-stable anisotropic magnetoresistance memory in antiferromagnetic MnTe. Nat. Commun. 7, 11623 (2016).
Zhang, J. et al. Strong magnetization and Chern insulators in compressed graphene/CrI3 van der Waals heterostructures. Phys. Rev. B 97, 085401 (2018).
Zhang, Y., Tan, Y.-W., Stormer, H. L. & Kim, P. Experimental observation of the quantum Hall effect and Berry’s phase in graphene. Nature 438, 201–204 (2005).
Gusynin, V. & Sharapov, S. Unconventional integer quantum Hall effect in graphene. Phys. Rev. Lett. 95, 146801 (2005).
Tan, Y.-W. et al. Measurement of scattering rate and minimum conductivity in graphene. Phys. Rev. Lett. 99, 246803 (2007).
Wang, Z. et al. Origin and magnitude of ‘designer’ spin–orbit interaction in graphene on semiconducting transition metal dichalcogenides. Phys. Rev. X 6, 041020 (2016).
Wang, Z. et al. Strong interface-induced spin–orbit interaction in graphene on WS2. Nat. Commun. 6, 8339 (2015).
The transport measurement and theoretical modelling in this work were supported by Spins and Heat in Nanoscale Electronic Systems (SHINES), an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under award #SC0012670. We are also grateful for support from the National Science Foundation (NSF) (DMR-1411085 and DMR-1810163) and the ARO programme (contract no. W911NF-15-1-10561). Research was performed in part at the NIST Center for Nanoscale Science and Technology. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF grant no. OCI-1053575. Specifically, it used the Bridges system (supported by NSF award no. ACI-1445606) at the Pittsburgh Supercomputing Center (PSC). Certain commercial equipment, instruments or materials are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Wu, Y., Yin, G., Pan, L. et al. Large exchange splitting in monolayer graphene magnetized by an antiferromagnet. Nat Electron 3, 604–611 (2020). https://doi.org/10.1038/s41928-020-0458-0