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.

Control of single-spin magnetic anisotropy by exchange coupling

Nature Nanotechnology volume 9, pages 64–68 (2014)Cite this article

Subjects

Abstract

The properties of quantum systems interacting with their environment, commonly called open quantum systems, can be affected strongly by this interaction. Although this can lead to unwanted consequences, such as causing decoherence in qubits used for quantum computation1, it can also be exploited as a probe of the environment. For example, magnetic resonance imaging is based on the dependence of the spin relaxation times of protons2 in water molecules in a host's tissue3. Here we show that the excitation energy of a single spin, which is determined by magnetocrystalline anisotropy and controls its stability and suitability for use in magnetic data-storage devices4, can be modified by varying the exchange coupling of the spin to a nearby conductive electrode. Using scanning tunnelling microscopy and spectroscopy, we observe variations up to a factor of two of the spin excitation energies of individual atoms as the strength of the spin's coupling to the surrounding electronic bath changes. These observations, combined with calculations, show that exchange coupling can strongly modify the magnetic anisotropy. This system is thus one of the few open quantum systems in which the energy levels, and not just the excited-state lifetimes, can be renormalized controllably. Furthermore, we demonstrate that the magnetocrystalline anisotropy, a property normally determined by the local structure around a spin, can be tuned electronically. These effects may play a significant role in the development of spintronic devices5 in which an individual magnetic atom or molecule is coupled to conducting leads.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

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

Figure 1: Spectroscopy of Co on a large (18.6 × 20.5 nm2) Cu2N island.
Figure 2: Generalized Anderson model of the Co electrons coupled to a bath of conduction electrons.
Figure 3: Magnetic-field dependence of differential conductance spectra of Co on 18.6 × 20.5 nm2 Cu2N island.

References

  1. DiVincenzo, D. P. Quantum computation. Science 270, 255–261 (1995).

    Article  CAS  Google Scholar 

  2. Damadian, R. Tumor detection by nuclear magnetic resonance. Science 171, 1151–1153 (1971).

    Article  CAS  Google Scholar 

  3. Pykett, I. L. et al. Principles of nuclear magnetic resonance imaging. Radiology 143, 157–168 (1982).

    Article  CAS  Google Scholar 

  4. Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, 2006).

    Book  Google Scholar 

  5. Bogani, L. & Wernsdorfer, W. Molecular spintronics using single-molecule magnets. Nature Mater. 7, 179–186 (2008).

    Article  CAS  Google Scholar 

  6. Cohen-Tannoudji, C., Dupont-Roc, J. & Grynberg, G. Atom–Photon Interactions (Wiley, 1992).

    Google Scholar 

  7. Hewson, A. C. The Kondo Problem to Heavy Fermions (Cambridge Univ. Press, 1997).

    Google Scholar 

  8. Loth, S., Baumann, S., Lutz, C. P., Eigler, D. M. & Heinrich, A. J. Bistability in atomic-scale antiferromagnets. Science 335, 196–199 (2012).

    Article  CAS  Google Scholar 

  9. Balashov, T. et al. Magnetic anisotropy and magnetization dynamics of individual atoms and clusters of Fe and Co on Pt(111). Phys. Rev. Lett. 102, 257203 (2009).

    Article  CAS  Google Scholar 

  10. Gambardella, P. et al. Giant magnetic anisotropy of single cobalt atoms and nanoparticles. Science 300, 1130–1133 (2003).

    Article  CAS  Google Scholar 

  11. Hirjibehedin, C. F. et al. Large magnetic anisotropy of a single atomic spin embedded in a surface molecular network. Science 317, 1199–1203 (2007).

    Article  CAS  Google Scholar 

  12. Meier, F., Zhou, L., Wiebe, J. & Wiesendanger, R. Revealing magnetic interactions from single-atom magnetization curves. Science 320, 82–86 (2008).

    Article  CAS  Google Scholar 

  13. Rusponi, S. et al. The remarkable difference between surface and step atoms in the magnetic anisotropy of two-dimensional nanostructures. Nature Mater. 2, 546–551 (2003).

    Article  CAS  Google Scholar 

  14. Tsukahara, N. et al. Adsorption-induced switching of magnetic anisotropy in a single iron(II) phthalocyanine molecule on an oxidized Cu(110) surface. Phys. Rev. Lett. 102, 167203 (2009).

    Article  Google Scholar 

  15. Parks, J. J. et al. Mechanical control of spin states in spin-1 molecules and the underscreened Kondo effect. Science 328, 1370–1373 (2010).

    Article  CAS  Google Scholar 

  16. Zyazin, A. S. et al. Electric field controlled magnetic anisotropy in a single molecule. Nano Lett. 10, 3307–3311 (2010).

    Article  CAS  Google Scholar 

  17. Höck, M. & Schnack, J. Numerical renormalization group calculations of the magnetization of isotropic and anisotropic Kondo impurities. Phys. Rev. B 87, 184408 (2013).

    Article  Google Scholar 

  18. Otte, A. F. et al. The role of magnetic anisotropy in the Kondo effect. Nature Phys. 4, 847–850 (2008).

    Article  CAS  Google Scholar 

  19. Romeike, C., Wegewijs, M., Hofstetter, W. & Schoeller, H. Quantum-tunneling-induced Kondo effect in single molecular magnets. Phys. Rev. Lett. 96, 196601 (2006).

    Article  CAS  Google Scholar 

  20. Abragam, A. & Bleaney, B. Electron Paramagnetic Resonance of Transition Ions (Oxford Univ. Press, 2012).

    Google Scholar 

  21. Ashcroft, N. W. & Mermin, N. D. Solid State Physics (Holt, Rinehart & Winston, 1976).

    Google Scholar 

  22. Delgado, F., Palacios, J. J. & Fernández-Rossier, J. Spin-transfer torque on a single magnetic adatom. Phys. Rev. Lett. 104, 026601 (2010).

    Article  CAS  Google Scholar 

  23. Khajetoorians, A. A. et al. Current-driven spin dynamics of artificially constructed quantum magnets. Science 339, 55–59 (2013).

    Article  CAS  Google Scholar 

  24. Loth, S. et al. Controlling the state of quantum spins with electric currents. Nature Phys. 6, 340–344 (2010).

    Article  CAS  Google Scholar 

  25. Slichter, C. P. Principles of Magnetic Resonance (Springer, 1978).

    Book  Google Scholar 

  26. Scalapino, D. Curie law for Anderson's model of a dilute alloy. Phys. Rev. Lett. 16, 937–939 (1966).

    Article  CAS  Google Scholar 

  27. Haule, K., Kirchner, S., Kroha, J. & Wölfle, P. Anderson impurity model at finite Coulomb interaction U: Generalized noncrossing approximation. Phys. Rev. B 64, 155111 (2001).

    Article  Google Scholar 

  28. Maltseva, M., Dzero, M. & Coleman, P. Electron cotunneling into a Kondo lattice. Phys. Rev. Lett. 103, 206402 (2009).

    Article  Google Scholar 

  29. Korytár, R., Lorente, N. & Gauyacq, J-P. Many-body effects in magnetic inelastic electron tunneling spectroscopy. Phys. Rev. B 85, 125434 (2012).

    Article  Google Scholar 

  30. Ruggiero, C. D. et al. Emergence of surface states in nanoscale Cu2N islands. Phys. Rev. B 83, 245430 (2011).

    Article  Google Scholar 

  31. Vitali, L. et al. Kondo effect in single atom contacts: the importance of the atomic geometry. Phys. Rev. Lett. 101, 216802 (2008).

    Article  Google Scholar 

  32. Zhang, L., Miyamachi, T., Tomanic, T., Dehm, R. & Wulfhekel, W. A compact sub-Kelvin ultrahigh vacuum scanning tunneling microscope with high energy resolution and high stability. Rev. Sci. Instrum. 82, 103702 (2011).

    Article  CAS  Google Scholar 

  33. Horcas, I. et al. WSXM: a software for scanning probe microscopy and a tool for nanotechnology. Rev. Sci. Instrum. 78, 013705 (2007).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We acknowledge B. E. M. Bryant, A. J. Fisher, K. J. Franke, A. J. Heinrich, M. Hybertsen, S. Loth and A. F. Otte for discussions and B. E. M. Bryant for support during the experiments. J.F-R. acknowledges the hospitality of the Max-Planck-Institut für Mikrostrukturphysik Halle. Also, J.F-R. is on leave from Departamento de Física Aplicada, Universidad de Alicante, Spain. This work was supported by the Engineering and Physical Sciences Research Council, UK (EP/D063604/1 and EP/H002022/1), Ministry of Science and Education Spain (FIS2010-21883-C02-01, MAT2010-19236, CONSOLIDER CSD2007-0010 and Programa de Movilidad Postdoctoral), European Commission FP7 Programme (PER-GA-2009-251791) and GV grant Prometeo 2012-11.

Author information

Author notes

  1. M. Reyes Calvo

    Present address: Present address: Department of Physics, Stanford University, Stanford, California 94305, USA,

  2. Jenny C. Oberg and M. Reyes Calvo: These authors contributed equally to this work

Authors and Affiliations

  1. London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK

    Jenny C. Oberg, M. Reyes Calvo & Cyrus F. Hirjibehedin

  2. Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK

    Jenny C. Oberg & Cyrus F. Hirjibehedin

  3. International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal

    Fernando Delgado & Joaquín Fernández-Rossier

  4. Instituto de Nanociencia de Aragón and Laboratorio de Microscopías Avanzadas, Universidad de Zaragoza, Zaragoza, 50018, Spain

    María Moro-Lagares & David Serrate

  5. Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, 50009, Spain

    María Moro-Lagares & David Serrate

  6. Max-Planck-Institut für Mikrostrukturphysik, Halle, 06120, Germany

    David Jacob

  7. Department of Chemistry, University College London, London, WC1H 0AJ, UK

    Cyrus F. Hirjibehedin

Authors
  1. Jenny C. Oberg
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. Reyes Calvo
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Fernando Delgado
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. María Moro-Lagares
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. David Serrate
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. David Jacob
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Joaquín Fernández-Rossier
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Cyrus F. Hirjibehedin
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

J.C.O, M.R.C. and C.F.H. conceived the experiments. J.C.O. and M.R.C. performed the primary experiments and the data analysis, supervised by C.F.H. Additional experiments were performed by J.C.O. with the assistance of M.M. and supervised by D.S. and C.F.H. F.D. performed the perturbative calculations of exchange-induced modification of magnetic anisotropy, as proposed by J.F-R. D.J. implemented and performed the Anderson model calculations in the OCA as proposed by J.F-R. All authors discussed the results and participated in writing the manuscript.

Corresponding author

Correspondence to Cyrus F. Hirjibehedin.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary Information (PDF 1863 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Oberg, J., Calvo, M., Delgado, F. et al. Control of single-spin magnetic anisotropy by exchange coupling. Nature Nanotech 9, 64–68 (2014). https://doi.org/10.1038/nnano.2013.264

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2013.264

This article is cited by

Search

Advanced search

Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research