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The Kondo effect in ferromagnetic atomic contacts


Iron, cobalt and nickel are archetypal ferromagnetic metals. In bulk, electronic conduction in these materials takes place mainly through the s and p electrons, whereas the magnetic moments are mostly in the narrow d-electron bands, where they tend to align. This general picture may change at the nanoscale because electrons at the surfaces of materials experience interactions that differ from those in the bulk. Here we show direct evidence for such changes: electronic transport in atomic-scale contacts of pure ferromagnets (iron, cobalt and nickel), despite their strong bulk ferromagnetism, unexpectedly reveal Kondo physics, that is, the screening of local magnetic moments by the conduction electrons below a characteristic temperature1. The Kondo effect creates a sharp resonance at the Fermi energy, affecting the electrical properties of the system; this appears as a Fano–Kondo resonance2 in the conductance characteristics as observed in other artificial nanostructures3,4,5,6,7,8,9,10,11. The study of hundreds of contacts shows material-dependent log-normal distributions of the resonance width that arise naturally from Kondo theory12. These resonances broaden and disappear with increasing temperature, also as in standard Kondo systems4,5,6,7. Our observations, supported by calculations, imply that coordination changes can significantly modify magnetism at the nanoscale. Therefore, in addition to standard micromagnetic physics, strong electronic correlations along with atomic-scale geometry need to be considered when investigating the magnetic properties of magnetic nanostructures.

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Figure 1: Conductance of a monatomic contact.
Figure 2: Histograms of inferred Kondo temperatures for iron, cobalt and nickel.
Figure 3: Evolution of the Fano resonances with increasing temperature.
Figure 4: Electronic structure for a nickel chain and a nickel nanocontact.

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  1. Kondo, J. Resistance minimum in dilute magnetic alloys. Prog. Theor. Phys. 32, 37–49 (1964)

    Article  ADS  CAS  Google Scholar 

  2. Fano, U. Effects of configuration interaction on intensities and phase shifts. Phys. Rev. 124, 1866–1878 (1961)

    Article  ADS  CAS  Google Scholar 

  3. Goldhaber-Gordon, D. et al. The Kondo effect in a single-electron transistor. Nature 391, 156–159 (1998)

    Article  ADS  CAS  Google Scholar 

  4. Cronenwett, S. M., Oosterkamp, T. H. & Kouwenhoven, L. P. A tunable Kondo effect in quantum dots. Science 281, 540–544 (1998)

    Article  ADS  CAS  Google Scholar 

  5. Park, J. et al. Coulomb blockade and the Kondo effect in single-atom transistors. Nature 417, 722–725 (2002)

    Article  ADS  CAS  Google Scholar 

  6. Liang, W., Shores, M. P., Bockrath, M., Long, J. R. & Park, H. Kondo resonance in a single-molecule transistor. Nature 417, 725–729 (2002)

    Article  ADS  CAS  Google Scholar 

  7. Nygard, J., Cobden, D. H. & Lindelof, P. E. Kondo physics in carbon nanotubes. Nature 408, 342–346 (2000)

    Article  ADS  CAS  Google Scholar 

  8. Yu, L. H. & Natelson, D. The Kondo effect in C60 single-molecule transistors. Nano Lett. 4, 79–83 (2003)

    Article  ADS  Google Scholar 

  9. Mandhavan, V., Chen, W., Jamneala, T., Crommie, M. F. & Wingreen, N. S. Tunneling into a single magnetic atom: spectroscopic evidence of the Kondo resonance. Science 280, 567–569 (1998)

    Article  ADS  Google Scholar 

  10. Li, J., Schneider, W. D., Berndt, R. & Delley, B. Kondo scattering observed at a single magnetic impurity. Phys. Rev. Lett. 80, 2893–2896 (1998)

    Article  ADS  CAS  Google Scholar 

  11. Néel, N. et al. Conductance and Kondo Effect in a controlled single-atom contact. Phys. Rev. Lett. 98, 016801 (2006)

    Article  ADS  Google Scholar 

  12. Hewson, A. C. The Kondo Problem to Heavy Fermions (Cambridge Univ. Press, 1993)

    Book  Google Scholar 

  13. Agraït, N., Levy-Yeyati, A. & van Ruitenbeek, J. M. Quantum properties of atomic-sized conductors. Phys. Rep. 377, 81–279 (2003)

    Article  ADS  Google Scholar 

  14. Park, H., Lim, A. K. L., Alivisatos, A. P., Park, J. & McEuen, P. L. Fabrication of metallic electrodes with nanometer separation by electromigration. Appl. Phys. Lett. 75, 301–303 (1994)

    Article  ADS  Google Scholar 

  15. Untiedt, C., Dekker, D. M. T., Djukic, D. & van Ruitenbeek, J. M. Absence of magnetically induced fractional quantization in atomic contacts. Phys. Rev. B 69, 081401 (2004)

    Article  ADS  Google Scholar 

  16. Jacob, D., Fernández-Rossier, J. & Palacios, J. J. Magnetic and orbital blocking in Ni nanocontacts. Phys. Rev. B 71, 220403 (2005)

    Article  ADS  Google Scholar 

  17. Calvo, M. R., Caturla, M. J., Jacob, D., Untiedt, C. & Palacios, J. J. Mechanical, electrical and magnetic properties of Ni nanocontacts. IEEE Trans. Nanotechnol. 7, 165–168 (2008)

    Article  ADS  Google Scholar 

  18. Jamneala, T., Madhavan, V., Chen, W. & Crommie, M. F. Scanning tunneling spectroscopy of transition-metal impurities at the surface of gold. Phys. Rev. B 61, 9990–9993 (2000)

    Article  ADS  CAS  Google Scholar 

  19. Keane, Z. K., Yu, L. H. & Natelson, D. Magnetoresistance of atomic-scale electromigrated nickel nanocontacts. Appl. Phys. Lett. 88, 062514–062516 (2006)

    Article  ADS  Google Scholar 

  20. van der Wiel, W. G. et al. The Kondo effect in the unitary limit. Science 289, 2105–2108 (2000)

    Article  ADS  CAS  Google Scholar 

  21. Pasupathy, A. N. et al. The Kondo effect in the presence of ferromagnetism. Science 306, 86–89 (2004)

    Article  ADS  CAS  Google Scholar 

  22. Hauptmann, J. R., Paaske, J. & Lindelof, P. E. Electric-field-controlled spin reversal in a quantum dot with ferromagnetic contacts. Nature Phys. 4, 373–376 (2008)

    Article  ADS  CAS  Google Scholar 

  23. Martinek, J. et al. Kondo effect in quantum dots coupled to ferromagnetic leads. Phys. Rev. Lett. 91, 127203 (2003)

    Article  ADS  CAS  Google Scholar 

  24. Martinek, J. et al. Kondo effect in the presence of itinerant-electron ferromagnetism studied with the numerical renormalization group method. Phys. Rev. Lett. 91, 247202 (2003)

    Article  ADS  CAS  Google Scholar 

  25. Anderson, P. W. Localized magnetic states in metals. Phys. Rev. 124, 41–53 (1961)

    Article  ADS  MathSciNet  CAS  Google Scholar 

  26. Schrieffer, J. R. & Wolf, P. A. Relation between the Anderson and Kondo Hamiltonians. Phys. Rev. 149, 491–492 (1966)

    Article  ADS  CAS  Google Scholar 

  27. Wierzbowska, M., Delin, A. & Tosatti, E. Effect of electron correlations in Pd, Ni, and Co nanowires. Phys. Rev. B 72, 035439 (2005)

    Article  ADS  Google Scholar 

  28. Pajda, M., Kudrnovský, J., Turek, I., Drchal, V. & Bruno, P. Ab initio calculations of exchange interactions, spin -wave stiffness constants, and Curie temperatures of Fe, Co, and Ni. Phys. Rev. B 64, 174402 (2001)

    Article  ADS  Google Scholar 

  29. Mook, H. A. & Paul, D. McK. Neutron-scattering measurement of the spin-wave spectra for nickel. Phys. Rev. Lett. 54, 227–230 (1985)

    Article  ADS  CAS  Google Scholar 

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We thank E. Tosatti, R. Aguado and J. Ferrer for discussions, G. Scott and G. Saenz-Arce for experimental support and V. Esteve for technical support. This work was partly supported by the European Union through MolSpinQIP and Spanish MEC (grants MAT2007-65487, 31099-E and CONSOLIDER CSD2007-0010). D.J. acknowledges funding by the US National Science Foundation (NSF) under grant DMR-0528969. D.N. acknowledges the support of NSF grant DMR-0347253, the David and Lucille Packard Foundation and the W. M. Keck Program in Quantum Materials.

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Correspondence to Carlos Untiedt.

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Calvo, M., Fernández-Rossier, J., Palacios, J. et al. The Kondo effect in ferromagnetic atomic contacts. Nature 458, 1150–1153 (2009).

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