Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Tunable spin injection and detection across a van der Waals interface

Abstract

Van der Waals heterostructures with two-dimensional magnets offer a magnetic junction with an atomically sharp and clean interface. This attribute ensures that the magnetic layers maintain their intrinsic spin-polarized electronic states and spin-flipping scattering processes at a minimum level, a trait that can expand spintronic device functionalities. Here, using a van der Waals assembly of ferromagnetic Fe3GeTe2 with non-magnetic hexagonal boron nitride and WSe2 layers, we demonstrate electrically tunable, highly transparent spin injection and detection across the van der Waals interfaces. By varying an electrical bias, the net spin polarization of the injected carriers can be modulated and reversed in polarity, which leads to sign changes of the tunnelling magnetoresistance. We attribute the spin polarization reversals to sizable contributions from high-energy localized spin states in the metallic ferromagnet, so far inaccessible in conventional magnetic junctions. Such tunability of the spin-valve operations opens a promising route for the electronic control of next-generation low-dimensional spintronic device applications.

This is a preview of subscription content, access via your institution

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Fig. 1: Energy-dependent spin-polarized electronic structures of Fe3GeTe2 and energy-band alignments of MTJs with localized minority spin states.
Fig. 2: Bias-tunable spin-valve operations of FGT-based all-vdW MTJs.
Fig. 3: Bias-driven TMR polarity switching in FGT-based all-vdW MTJs.
Fig. 4: Bias-dependent TMR polarity switching in various MTJs.

Data availability

All data supporting the findings of this study are available from the corresponding authors on request.

References

  1. Morosov, A. I. Ferromagnetic magnetization switching by an electric field: a review. Phys. Solid State 56, 865–872 (2014).

    CAS  Article  Google Scholar 

  2. Dietl, T. A ten-year perspective on dilute magnetic semiconductors and oxides. Nat. Mater. 9, 965–974 (2010).

    CAS  Article  Google Scholar 

  3. Heron, J. T. et al. Electric-field-induced magnetization reversal in a ferromagnet-multiferroic heterostructure. Phys. Rev. Lett. 107, 217202 (2011).

    CAS  Article  Google Scholar 

  4. Gibertini, M., Koperski, M., Morpurgo, A. F. & Novoselov, K. S. Magnetic 2D materials and heterostructures. Nat. Nanotechnol. 14, 408–419 (2019).

    CAS  Article  Google Scholar 

  5. Gong, C. & Zhang, X. Two-dimensional magnetic crystals and emergent heterostructure devices. Science 363, eaav4450 (2019).

    CAS  Article  Google Scholar 

  6. Huang, B. et al. Emergent phenomena and proximity effects in 2D magnets and heterostructures. Nat. Mater. 19, 1276–1289 (2020).

    CAS  Article  Google Scholar 

  7. Huang, B. et al. Electrical control of 2D magnetism in bilayer CrI3. Nat. Nanotechnol. 13, 544–548 (2018).

    CAS  Article  Google Scholar 

  8. Jiang, S., Li, L., Wang, Z., Mak, K. F. & Shan, J. Controlling magnetism in 2D CrI3 by electrostatic doping. Nat. Nanotechnol. 13, 549–553 (2018).

    CAS  Article  Google Scholar 

  9. Žutić, I., Fabian, J. & Sarma, S. D. Spintronics: fundamentals and applications. Rev. Mod. Phys. 76, 323–410 (2004).

    Article  CAS  Google Scholar 

  10. Zhang, S., Levy, P. M., Marley, A. C. & Parkin, S. S. P. Quenching of magnetoresistance by hot electrons in magnetic tunnel junctions. Phys. Rev. Lett. 79, 3744–3747 (1997).

    CAS  Article  Google Scholar 

  11. Jansen, R. & Moodera, J. S. Influence of barrier impurities on the magnetoresistance in ferromagnetic tunnel junctions. J. Appl. Phys. 83, 6682–6684 (1998).

    CAS  Article  Google Scholar 

  12. Zhang, S. Spin Hall effect in the presence of spin diffusion. Phys. Rev. Lett. 85, 393–396 (2000).

    CAS  Article  Google Scholar 

  13. Vera Marún, I. J., Postma, F. M., Lodder, J. C. & Jansen, R. Tunneling magnetoresistance with positive and negative sign in La0.67Sr0.33MnO3/SrTiO3/Co junctions. Phys. Rev. B 76, 064426 (2007).

    Article  CAS  Google Scholar 

  14. Heiliger, C., Zahn, P., Yavorsky, B. Y. & Mertig, I. Influence of the interface structure on the bias dependence of tunneling magnetoresistance. Phys. Rev. B 72, 180406(R) (2005).

    Article  CAS  Google Scholar 

  15. Yang, S., Zhang, T. & Jiang, C. Van der Waals magnets: material family, detection and modulation of magnetism, and perspective in spintronics. Adv. Sci. 8, 2002488 (2021).

    CAS  Article  Google Scholar 

  16. Han, W., Maekawa, S. & Xie, X. C. Spin current as a probe of quantum materials. Nat. Mater. 19, 139–152 (2020).

    CAS  Article  Google Scholar 

  17. Yuasa, S., Fukushima, A., Nagahama, T., Ando, K. & Suzuki, Y. High tunnel magnetoresistance at room temperature in fully epitaxial Fe/MgO/Fe tunnel junctions due to coherent spin-polarized tunneling. Jpn. J. Appl. Phys. 43, L588–L590 (2004).

    CAS  Article  Google Scholar 

  18. Deiseroth, H. J., Aleksandrov, K., Reiner, C., Kienle, L. & Kremer, R. K. Fe3GeTe2 and Ni3GeTe2 – two new layered transition-metal compounds: crystal structures, HRTEM investigations, and magnetic and electrical properties. Eur. J. Inorg. Chem. 8, 1561–1567 (2006).

    Article  CAS  Google Scholar 

  19. May, A. F., Calder, S., Cantoni, C., Cao, H. & McGuire, M. A. Magnetic structure and phase stability of the van der Waals bonded ferromagnet Fe3–xGeTe2. Phys. Rev. B 93, 014411 (2016).

    Article  CAS  Google Scholar 

  20. Zhuang, H. L., Kent, P. R. C. & Hennig, R. G. Strong anisotropy and magnetostriction in the two-dimensional Stoner ferromagnet Fe3GeTe2. Phys. Rev. B 93, 134407 (2016).

    Article  CAS  Google Scholar 

  21. Tan, C. et al. Hard magnetic properties in nanoflake van der Waals Fe3GeTe2. Nat. Commun. 9, 1554 (2018).

    Article  CAS  Google Scholar 

  22. Liu, S. et al. Wafer-scale two-dimensional ferromagnetic Fe3GeTe2 thin films grown by molecular beam epitaxy. npj 2D Mater. Appl. 1, 30 (2017).

    Article  CAS  Google Scholar 

  23. Fei, Z. et al. Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2. Nat. Mater. 17, 778–782 (2018).

    CAS  Article  Google Scholar 

  24. Kim, K. et al. Large anomalous Hall current induced by topological nodal lines in a ferromagnetic van der Waals semimetal. Nat. Mater. 17, 794–799 (2018).

    CAS  Article  Google Scholar 

  25. Seo, J. et al. Nearly room temperature ferromagnetism in a magnetic metal-rich van der Waals metal. Sci. Adv. 6, eaay8912 (2020).

    Article  CAS  Google Scholar 

  26. Zhang, Y. et al. Emergence of Kondo lattice behavior in a van der Waals itinerant ferromagnet, Fe3GeTe2. Sci. Adv. 4, eaao6791 (2018).

    Article  CAS  Google Scholar 

  27. Xu, X. et al. Signature for non-Stoner ferromagnetism in the van der Waals ferromagnet Fe3GeTe2. Phys. Rev. B 101, 201104(R) (2020).

    Article  Google Scholar 

  28. Wang, Z. et al. Tunneling spin valves based on Fe3GeTe2/hBN/Fe3GeTe2 van der Waals heterostructures. Nano Lett. 18, 4303–4308 (2018).

    CAS  Article  Google Scholar 

  29. Lin, H. et al. Spin-valve effect in Fe3GeTe2/MoS2/Fe3GeTe2 van der Waals heterostructures. ACS Appl. Mater. Interfaces 12, 43921–43926 (2020).

    CAS  Article  Google Scholar 

  30. Nazir, G. et al. Ultimate limit in size and performance of WSe2 vertical diodes. Nat. Commun. 9, 5371 (2018).

    CAS  Article  Google Scholar 

  31. Jang, S. W. et al. Origin of ferromagnetism and the effect of doping on Fe3GeTe2. Nanoscale 12, 13501–13506 (2020).

    CAS  Article  Google Scholar 

  32. Li, X. et al. Spin-dependent transport in van der Waals magnetic tunnel junctions with Fe3GeTe2 electrodes. Nano Lett. 19, 5133–5139 (2019).

    CAS  Article  Google Scholar 

  33. Tiusan, C. et al. Interfacial resonance state probed by spin-polarized tunneling in epitaxial Fe/MgO/Fe tunnel junctions. Phys. Rev. Lett. 93, 106602 (2004).

    CAS  Article  Google Scholar 

  34. De Teresa, J. M. et al. Inverse tunnel magnetoresistance in Co/SrTiO3/La0.7Sr0.3MnO3: new ideas on spin-polarized tunneling. Phys. Rev. Lett. 82, 4288–4291 (1999).

    Article  Google Scholar 

  35. Asshoff, P. U. et al. Magnetoresistance of vertical Co-graphene-NiFe junctions controlled by charge transfer and proximity-induced spin splitting in graphene. 2D Mater. 4, 031004 (2017).

    Article  CAS  Google Scholar 

  36. Piquemal-Banci, M. et al. Insulator-to-metallic spin-filtering in 2D-magnetic tunnel junctions based on hexagonal boron nitride. ACS Nano 12, 4712–4718 (2018).

    CAS  Article  Google Scholar 

  37. Gangineni, R. B. et al. Interfacial electronic transport phenomena in single crystalline Fe-MgO-Fe thin barrier junctions. Appl. Phys. Lett. 104, 182402 (2014).

    Article  CAS  Google Scholar 

  38. Godel, F. et al. Voltage-controlled inversion of tunnel magnetoresistance in epitaxial nickel/graphene/MgO/cobalt junctions. Appl. Phys. Lett. 105, 152407 (2014).

    Article  CAS  Google Scholar 

  39. Dorneles, L. S., Sommer, R. L. & Schelp, L. F. Tunnel magnetoresistance in NiFe/TaOx/Al2O3/Co junctions with a thin TaOx layer. J. Appl. Phys. 91, 7971–7973 (2002).

    CAS  Article  Google Scholar 

  40. Tanaka, M. A. et al. Bias-voltage-dependence of magnetoresistance for epitaxial Fe/MgO/Co2MnSn tunnel junctions. J. Phys. Conf. Ser. 266, 012107 (2011).

    Article  CAS  Google Scholar 

  41. Kalitsov, A. et al. Bias dependence of tunneling magnetoresistance in magnetic tunnel junctions with asymmetric barriers. J. Phys. Condens. Matter 25, 496005 (2013).

    Article  CAS  Google Scholar 

  42. Chappert, C., Fert, A. & Van Dau, F. N. The emergence of spin electronics in data storage. Nat. Mater. 6, 813–823 (2007).

    CAS  Article  Google Scholar 

  43. Dery, H., Dalal, P., Cywiński, Ł. & Sham, L. J. Spin-based logic in semiconductors for reconfigurable large-scale circuits. Nature 447, 573–576 (2007).

    CAS  Article  Google Scholar 

  44. Quay, C. H. L., Chevallier, D., Bena, C. & Aprili, M. Spin imbalance and spin-charge separation in a mesoscopic superconductor. Nat. Phys. 9, 84–88 (2013).

    CAS  Article  Google Scholar 

  45. Lin, M. W. et al. Ultrathin nanosheets of CrSiTe3: a semiconducting two-dimensional ferromagnetic material. J. Mater. Chem. C 4, 315–322 (2016).

    CAS  Article  Google Scholar 

  46. Belianinov, A. et al. CuInP2S6 room temperature layered ferroelectric. Nano Lett. 15, 3808–3814 (2015).

    CAS  Article  Google Scholar 

  47. Moodera, J. S., Miao, G. X. & Santos, T. S. Frontiers in spin-polarized tunneling. Phys. Today 63, 46–51 (2010).

    CAS  Article  Google Scholar 

  48. Kim, S. et al. Highly efficient experimental approach to evaluate metal to 2D semiconductor interfaces in vertical diodes with asymmetric metal contacts. ACS Appl. Mater. Interfaces 13, 27705–27712 (2021).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

K.-H.M., D.H.L., I.-H.L., D.H.H. and S.J. were supported by research grants for basic research funded by the Korea Research Institute of Standards and Science (no. KRISS-2020-GP20011059). J.E. and S.J. also acknowledge the support from the Basic Science Research Program through the National Research Foundation of Korea under grant nos NRF-2021R1A4A1031900 and NRF-2022R1A2C2008140. J.S. and J.S.K. were supported by the Institute for Basic Science through the Center for Artificial Low Dimensional Electronic Systems (IBS-R014-D1) and by the National Research Foundation of Korea (NRF-2022R1A2C3009731) and the Max Planck POSTECH/Korea Research Initiative (NRF-2022M3H4A1A04074153 and NRF-2020M3H4A2084417). S.-J.C. was also supported by the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter (EXC2147, project-id 390858490) and by the German Research Foundation (SPP1666 and SFB1170 ‘ToCoTronics’). C.K. acknowledges the support by the Institute for Basic Science in Korea (IBS-R009-G2).

Author information

Authors and Affiliations

Authors

Contributions

J.E., J.S.K. and S.J. conceived the experiments. K.-H.M. and D.H.L. fabricated the devices, conducted magneto-transport measurements and analysed the data. J.S. synthesized the FGT crystals under the supervision of J.S.K.; S.-J.C. established the theoretical model for vertical spin-dependent charge transport. I.-H.L., D.W.K. and J.H.S. performed electronic structure calculations and analyses. D.H.H. confirmed the WSe2 layer number with Raman and photoluminescence measurements, and K.-T.K. and C.K. performed the photoemission spectroscopy measurements on FGT crystals. K.W. and T.T. synthesized high-quality hBN crystals. K.-H.M., J.S.K., J.E. and S.J. cowrote the manuscript. All authors discussed the results and contributed to completing the manuscript.

Corresponding authors

Correspondence to Jonghwa Eom, Jun Sung Kim or Suyong Jung.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Materials thanks Zhe Wang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–8.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Min, KH., Lee, D.H., Choi, SJ. et al. Tunable spin injection and detection across a van der Waals interface. Nat. Mater. (2022). https://doi.org/10.1038/s41563-022-01320-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1038/s41563-022-01320-3

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing