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.

  • Letter
  • Published:

Observation of magnetic vortex pairs at room temperature in a planar α-Fe2O3/Co heterostructure

Nature Materials volume 17, pages 581–585 (2018)Cite this article

Subjects

Abstract

Vortices, occurring whenever a flow field ‘whirls’ around a one-dimensional core, are among the simplest topological structures, ubiquitous to many branches of physics. In the crystalline state, vortex formation is rare, since it is generally hampered by long-range interactions: in ferroic materials (ferromagnetic and ferroelectric), vortices are observed only when the effects of the dipole–dipole interaction are modified by confinement at the nanoscale1,2,3, or when the parameter associated with the vorticity does not couple directly with strain4. Here, we observe an unprecedented form of vortices in antiferromagnetic haematite (α-Fe2O3) epitaxial films, in which the primary whirling parameter is the staggered magnetization. Remarkably, ferromagnetic topological objects with the same vorticity and winding number as the α-Fe2O3 vortices are imprinted onto an ultra-thin Co ferromagnetic over-layer by interfacial exchange. Our data suggest that the ferromagnetic vortices may be merons (half-skyrmions, carrying an out-of plane core magnetization), and indicate that the vortex/meron pairs can be manipulated by the application of an in-plane magnetic field, giving rise to large-scale vortex–antivortex annihilation.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Vector map of the α-Fe2O3 antiferromagnetic domain configuration from X-ray photoemission microscopy.
Fig. 2: Magnetic domain structure of α-Fe2O3/Co film.
Fig. 3: Topological defects in α-Fe2O3 and Co.
Fig. 4: Vortex annihilation with an ex-situ applied field.

Similar content being viewed by others

References

  1. Zheng, Y. & Chen, W. Characteristics and controllability of vortices in ferromagnetics, ferroelectrics and multiferroics. Rep. Prog. Phys. 80, 086501 (2017).

    Article  Google Scholar 

  2. Yadav, A. K. et al. Observation of polar vortices in oxide superlattices. Nature 530, 198–201 (2016).

    Article  Google Scholar 

  3. Cowburn, R. P., Koltsov, D. K., Adeyeye, A. O., Welland, M. E. & Tricker, D. M. Single-domain circular nanomagnets. Phys. Rev. Lett. 83, 1042 (1999).

    Article  Google Scholar 

  4. Choi, T. et al. Insulating interlocked ferroelectric and structural antiphase domain walls in multiferroic YMnO3. Nat. Mater. 9, 253–258 (2010).

    Article  Google Scholar 

  5. Hallsteinsen, I. et al. Magnetic domain configuration of (111)-oriented LaFeO3 epitaxial thin films. APL Mater. 5, 086107 (2017).

    Article  Google Scholar 

  6. Waterfield Price, N. et al. Coherent magnetoelastic domains in multiferroic BiFeO3 films. Phys. Rev. Lett. 117, 177601 (2016).

    Article  Google Scholar 

  7. Alders, D. et al. Magnetic x-ray dichroism study of the nearest-neighbor spin-spin correlation function and long-range magnetic order parameter in antiferromagnetic NiO. Europhys. Lett. 32, 259 (1995).

    Article  Google Scholar 

  8. Scholl, A., Ohldag, H., Nolting, F., Stöhr, J. & Padmore, H. A. X-ray photoemission electron microscopy, a tool for the investigation of complex magnetic structures. Rev. Sci. Instrum. 73, 1362–1366 (2002).

    Article  Google Scholar 

  9. Chen, P., Lee, N., McGill, S., Cheong, S.-W. & Musfeldt, J. Magnetic-field-induced color change in α-Fe2O3 single crystals. Phys. Rev. B 85, 174413 (2012).

    Article  Google Scholar 

  10. Marmeggi, J. C., Hohlwein, D. & Bertaut, E. F. Magnetic neutron Laue diffraction study of the domain distribution in α-Fe2O3. Phys. Stat. Sol. (a) 39, 57–64 (1977).

    Article  Google Scholar 

  11. Nehring, J. & Saupe, A. On the schlieren texture in nematic and smectic liquid crystals. J. Chem. Soc. Faraday Trans. 2 68, 1–15 (1972).

    Article  Google Scholar 

  12. Chae, S. C. et al. Direct observation of the proliferation of ferroelectric loop domains and vortex-antivortex pairs. Phys. Rev. Lett. 108, 167603 (2012).

    Article  Google Scholar 

  13. Artyukhin, S., Delaney, K. T., Spaldin, N. A. & Mostovoy, M. Landau theory of topological defects in multiferroic hexagonal manganites. Nat. Mater. 13, 42–49 (2013).

    Article  Google Scholar 

  14. Kibble, T. W. B. Topology of cosmic domains and strings. J. Phys. A 9, 1387–1398 (1976).

    Article  Google Scholar 

  15. Zurek, W. H. Cosmological experiments in superfluid helium? Nature 317, 505–508 (1985).

    Article  Google Scholar 

  16. Meier, Q. N. et al. Global formation of topological defects in the multiferroic hexagonal manganites. Phys. Rev. X 7, 041014 (2017).

    Google Scholar 

  17. Kosterlitz, J. M. & Thouless, D. J. Ordering, metastability and phase transitions in two-dimensional systems. J. Phys. C 6, 1181–1203 (1973).

    Article  Google Scholar 

  18. Sort, J. et al. Imprinting vortices into antiferromagnets. Phys. Rev. Lett. 97, 067201 (2006).

    Article  Google Scholar 

  19. Wu, J. et al. Direct observation of imprinted antiferromagnetic vortex states in CoO/Fe/Ag(001) discs. Nat. Phys. 7, 303–306 (2011).

    Article  Google Scholar 

  20. Wintz, S. et al. Topology and origin of effective spin meron pairs in ferromagnetic multilayer elements. Phys. Rev. Lett. 110, 177201 (2013).

    Article  Google Scholar 

  21. Shinjo, T., Okuno, T., Hassdorf, R., Shigeto, K. & Ono, T. Magnetic vortex core observation in circular dots of permalloy. Science 289, 930–932 (2000).

    Article  Google Scholar 

  22. Senthil, T., Vishwanath, A., Balents, L., Sachdev, S. & Fisher, M. P. Deconfined quantum critical points. Science 303, 1490–1494 (2004).

    Article  Google Scholar 

  23. Griffin, S. M. et al. Scaling behavior and beyond equilibrium in the hexagonal manganites. Phys. Rev. X 2, 041022 (2012).

    Google Scholar 

  24. Shimomura, N. et al. Morin transition temperature in (0001)-oriented α-Fe2O3 thin film and effect of Ir doping. J. Appl. Phys. 117, 17C736 (2015).

    Article  Google Scholar 

  25. Yu, Y.-S., Jung, H., Lee, K.-S., Fischer, P. & Kim, S.-K. Memory-bit selection and recording by rotating fields in vortex-core cross-point architecture. Appl. Phys. Lett. 98, 052507 (2011).

    Article  Google Scholar 

  26. Nakano, K. et al. All-electrical operation of magnetic vortex core memory cell. Appl. Phys. Lett. 99, 262505 (2011).

    Article  Google Scholar 

  27. Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).

    Article  Google Scholar 

  28. Tomasello, R. et al. A strategy for the design of skyrmion racetrack memories. Sci. Rep. 4, 6784 (2014).

    Article  Google Scholar 

  29. Okada, K. & Kotani, A. Complementary roles of Co 2p X-ray absorption and photoemission spectra in CoO. J. Phys. Soc. Jpn 61, 449–453 (1992).

    Article  Google Scholar 

  30. Van der Laan, G. & Kirkman, I. W. The 2p absorption spectra of 3d transition metal compounds in tetrahedral and octahedral symmetry. J. Phys. Condens. Matter 4, 4189–4204 (1992).

    Article  Google Scholar 

  31. Stöhr, J. & Siegmann, H. C. Magnetism: From Fundamentals to Nanoscale Dynamics (Springer, Berlin, Heidelberg, 2006).

  32. Arenholz, E., van der Laan, G., Chopdekar, R. V. & Suzuki, Y. Anisotropic X-ray magnetic linear dichroism at the Fe L2,3 edges in Fe3O4. Phys. Rev. B 74, 094407 (2006).

    Article  Google Scholar 

Download references

Acknowledgements

We acknowledge Diamond Light Source for time on Beam Line I06 under Proposals SI16338 and SI15088. We thank S. Parameswaran for discussions and T. Hesjedal and S. Zhang for assistance with initial film growth. The work done at the University of Oxford (F.P.C., N.W.P., R.D.J. and P.G.R.) is funded by EPSRC grant no. EP/M020517/1, entitled Oxford Quantum Materials Platform grant. The work at University of Wisconsin-Madison (J.S., J.I., M.S.R. and C.-B.E.) is supported by the Army Research Office through grant nos W911NF-13-1-0486 and W911NF-17-1-0462. R.D.J. acknowledges support from a Royal Society University Research Fellowship.

Author information

Authors and Affiliations

  1. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK

    F. P. Chmiel, N. Waterfield Price, R. D. Johnson & P. G. Radaelli

  2. Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK

    A. D. Lamirand & G. van der Laan

  3. Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA

    J. Schad, D. T. Harris & C.-B. Eom

  4. Department of Physics, University of Wisconsin-Madison, Madison, WI, USA

    J. Irwin & M. S. Rzchowski

Authors
  1. F. P. Chmiel
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. N. Waterfield Price
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. R. D. Johnson
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. A. D. Lamirand
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. J. Schad
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. G. van der Laan
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. D. T. Harris
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. J. Irwin
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. M. S. Rzchowski
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. C.-B. Eom
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. P. G. Radaelli
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

F.P.C., N.W.P., R.D.J. and A.D.L. performed the experiment. F.P.C. and A.D.L. performed the data reduction. F.P.C and N.W.P. performed the data analysis. J.S grew the films. D.T.H. made the α-Fe2O3 sputtering target. J.S and F.P.C. characterized the epitaxial relation of the films. J.I. performed the MOKE measurement. G.v.L. performed calculations of the XMLD signal. N.W.P. performed the micromagnetic simulations. P.G.R conceived and designed the experiment and supervised the analysis together with R.D.J, while C.-B.E. supervised the film growth. M.S.R. supervised the MOKE measurement. P.G.R. and F.P.C. prepared the first draft of the manuscript. All authors discussed and contributed to the manuscript.

Corresponding authors

Correspondence to C.-B. Eom or P. G. Radaelli.

Ethics declarations

Competing interests

The authors declare no competing interests.

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 Notes, Supplementary Figures 1–7, Supplementary References 1–3

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Chmiel, F.P., Waterfield Price, N., Johnson, R.D. et al. Observation of magnetic vortex pairs at room temperature in a planar α-Fe2O3/Co heterostructure. Nature Mater 17, 581–585 (2018). https://doi.org/10.1038/s41563-018-0101-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41563-018-0101-x

This article is cited by

Search

Advanced 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