Abstract
The study of atomically thin ferromagnetic crystals has led to the discovery of unusual magnetic behaviour and provided insight into the magnetic properties of bulk materials. However, the experimental techniques that have been used to explore ferromagnetism in such materials cannot probe the magnetic field directly. Here, we show that ballistic Hall micromagnetometry can be used to measure the magnetization of individual two-dimensional ferromagnets. Our devices are made by van der Waals assembly in such a way that the investigated ferromagnetic crystal is placed on top of a multi-terminal Hall bar made from encapsulated graphene. We use the micromagnetometry technique to study atomically thin chromium tribromide (CrBr3). We find that the material remains ferromagnetic down to monolayer thickness and exhibits strong out-of-plane anisotropy. We also find that the magnetic response of CrBr3 varies little with the number of layers and its temperature dependence cannot be described by the simple Ising model of two-dimensional ferromagnetism.
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Data availability
The data that support our findings are available from the corresponding authors upon reasonable request.
Code availability
The computer code used in this study is available from the corresponding authors upon reasonable request.
References
Gong, C. et al. Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals. Nature 546, 265–269 (2017).
Huang, B. et al. Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit. Nature 546, 270–273 (2017).
Song, T. et al. Giant tunneling magnetoresistance in spin-filter van der Waals heterostructures. Science 360, 1214–1218 (2018).
Klein, D. R. et al. Probing magnetism in 2D van der Waals crystalline insulators via electron tunneling. Science 360, 1218–1222 (2018).
Ghazaryan, D. et al. Magnon-assisted tunnelling in van der Waals heterostructures based on CrBr3. Nat. Electron. 1, 344–349 (2018).
Wang, Z. et al. Very large tunneling magnetoresistance in layered magnetic semiconductor CrI3. Nat. Commun. 9, 2516 (2018).
Fei, Z. et al. Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2. Nat. Mater. 17, 778–782 (2018).
Seyler, K. L. et al. Ligand-field helical luminescence in a 2D ferromagnetic insulator. Nat. Phys. 14, 277–281 (2018).
Yao, T., Mason, J. G., Huiwen, J., Cava, R. J. & Kenneth, S. B. Magneto-elastic coupling in a potential ferromagnetic 2D atomic crystal. 2D Mater. 3, 025035 (2016).
Burch, K. S., Mandrus, D. & Park, J.-G. Magnetism in two-dimensional van der Waals materials. Nature 563, 47–52 (2018).
Jiang, S., Shan, J. & Mak, K. F. Electric-field switching of two-dimensional van der Waals magnets. Nat. Mater. 17, 406–410 (2018).
Huang, B. et al. Electrical control of 2D magnetism in bilayer CrI3. Nat. Nanotechnol. 13, 544–548 (2018).
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).
Wang, Z. et al. Electric-field control of magnetism in a few-layered van der Waals ferromagnetic semiconductor. Nat. Nanotechnol. 13, 554–559 (2018).
Song, T. et al. Voltage control of a van der Waals spin-filter magnetic tunnel junction. Nano Lett. 19, 915–920 (2019).
Abramchuk, M. et al. Controlling magnetic and optical properties of the van der Waals crystal CrCl3−xBrx via mixed halide chemistry. Adv. Mater. 30, 1801325 (2018).
McGuire, M. Crystal and magnetic structures in layered, transition metal dihalides and trihalides. Crystals 7, 121 (2017).
Zhong, D. et al. Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics. Sci. Adv. 3, e1603113 (2017).
Geim, A. K. et al. Phase transitions in individual sub-micrometre superconductors. Nature 390, 259–262 (1997).
Novoselov, K. S., Geim, A. K., Dubonos, S. V., Hill, E. W. & Grigorieva, I. V. Subatomic movements of a domain wall in the Peierls potential. Nature 426, 812–816 (2003).
Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013).
Cao, Y. et al. Quality heterostructures from two-dimensional crystals unstable in air by their assembly in inert atmosphere. Nano Lett. 15, 4914–4921 (2015).
Mayorov, A. S. et al. Micrometer-scale ballistic transport in encapsulated graphene at room temperature. Nano Lett. 11, 2396–2399 (2011).
Shcherbakov, D. et al. Raman spectroscopy, photocatalytic degradation, and stabilization of atomically thin chromium tri-iodide. Nano Lett. 18, 4214–4219 (2018).
Skomski, R., Oepen, H. P. & Kirschner, J. Micromagnetics of ultrathin films with perpendicular magnetic anisotropy. Phys. Rev. B 58, 3223–3227 (1998).
Christian, D. A., Novoselov, K. S. & Geim, A. K. Barkhausen statistics from a single domain wall in thin films studied with ballistic Hall magnetometry. Phys. Rev. B 74, 064403 (2006).
Ho, J. T. & Litster, J. D. Divergences of the magnetic properties of CrBr3 near the critical point. J. Appl. Phys. 40, 1270–1271 (1969).
Vaz, C. A. F., Bland, J. A. C. & Lauhoff, G. Magnetism in ultrathin film structures. Rep. Prog. Phys. 71, 056501 (2008).
Xu, C., Feng, J., Xiang, H. & Bellaiche, L. Interplay between Kitaev interaction and single ion anisotropy in ferromagnetic CrI3 and CrGeTe3 monolayers. npj Comput. Mater. 4, 57 (2018).
Banerjee, A. et al. Neutron scattering in the proximate quantum spin liquid α-RuCl3. Science 356, 1055–1059 (2017).
Liu, S. et al. Single crystal growth of millimeter-sized monoisotopic hexagonal boron nitride. Chem. Mater. 30, 6222–6622 (2018).
Wang, L. et al. One-dimensional electrical contact to a two-dimensional material. Science 342, 614–617 (2013).
Ben Shalom, M. et al. Quantum oscillations of the critical current and high-field superconducting proximity in ballistic graphene. Nat. Phys. 12, 318–322 (2016).
Frisenda, R. et al. Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials. Chem. Soc. Rev. 47, 53–68 (2018).
Novoselov, K. S. et al. Submicron probes for Hall magnetometry over the extended temperature range from helium to room temperature. J. Appl. Phys. 93, 10053–10057 (2003).
Acknowledgements
This work was supported by the European Research Council, the Graphene Flagship and Lloyd’s Register Foundation. M.K. was partly supported by the National Research Foundation of Korea (grant 2018R1A6A3A03010943). W.K., D.G.H. and A.I.B. were supported by the Graphene NowNANO Doctoral Training Programme. J.H.E. and S.L. acknowledge support from the NSF (grant CMMI 1538127).
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M.K. and P.K. carried out the project and analysed the experimental data. A.K.G. suggested and supervised the project. P.K., J.B. and S.G.X. fabricated devices. M.K., A.I.B. and W.K. performed electrical and superconducting quantum interference device measurements. D.G.H. and S.J.H. provided transmission electron microscopy analysis. M.K. performed the finite-element simulations. J.K. and P.A.M. provided theoretical support. S.L. and J.H.E. supplied hBN crystals. M.K., P.K., K.S.N., I.V.G., J.B. and A.K.G. wrote the manuscript. All of the authors contributed to discussions.
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Kim, M., Kumaravadivel, P., Birkbeck, J. et al. Micromagnetometry of two-dimensional ferromagnets. Nat Electron 2, 457–463 (2019). https://doi.org/10.1038/s41928-019-0302-6
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DOI: https://doi.org/10.1038/s41928-019-0302-6
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