High Resolution Magnetic Imaging by Local Tunneling Magnetoresistance

  • W. Wulfhekel
Part of the NanoScience and Technology book series (NANO)


An introduction to spin-polarized scanning tunneling microscopy with a soft magnetic tip is given. After illustrating the fundamental physical effect of tunneling magnetoresistance and giving a short historical background, it is shown how magnetic and topographic information can be separated using a modulation technique of the tip magnetization. Important for the functionality of the method is to avoid magnetostriction in the tip during reversal of its magnetization. It is shown that this is theoretically and experimentally possible with an appropriate tip material of very low magnetostriction. The closure domain structure of Co(0001) is studied and ultrasharp 20. domain walls of only 1.1 nm width are found. This narrow width is explained on the basis of a micromagnetic model, and a lateral resolution of the technique better than 1 nm is shown. The limits of the technique due to the stray field of the magnetic tip are illustrated. In the case that the stray field of the tip influences the sample under investigation, the local magnetic susceptibility can be measured. Furthermore, we focus on the contrast mechanism and give evidence that the tunneling magnetoresistance depends on the barrier height in agreement with Slonczewski's model. Finally, the possibility of magnetic imaging through a non-magnetic overlayer is discussed.


Domain Wall Barrier Height Spin Polarization Tunneling Current Scanning Tunneling Microscopy Image 
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  1. 1.
    G. Binning, H. Rohrer, Ch. Gerber, and E. Weibel, Appl. Phys. Lett. 40, 178 (1982).CrossRefGoogle Scholar
  2. 2.
    G. Binning, H. Rohrer, Ch. Gerber, and E. Weibel, Phys. Rev. Lett. 49, 57 (1982).CrossRefGoogle Scholar
  3. 3.
    M. Jullière, Phys. Lett. 54A, 225 (1975).Google Scholar
  4. 4.
    J.C. Slonczewski, Phys. Rev. B 39, 6995 (1989).CrossRefGoogle Scholar
  5. 5.
    T. Miyazaki and N. Tezuka, J. Magn. Magn. Mater. 139, L231 (1995).Google Scholar
  6. 6.
    D.T. Pierce and F. Meier, Phys. Rev. B 13, 5484 (1976).CrossRefGoogle Scholar
  7. 7.
    M. Johnson and J. Clarke, J. Appl. Phys. 67, 6141 (1990).CrossRefGoogle Scholar
  8. 8.
    R. Wiesendanger, H.J. Güntherodt, G. Güntherodt, R.J. Gambino, and R. Ruf, Phys. Rev. Lett. 65, 247 (1990).CrossRefGoogle Scholar
  9. 9.
    S. Blügel, D. Pescia, and P.H. Dederichs, Phys. Rev. B 39, 1392 (1989).CrossRefGoogle Scholar
  10. 10.
    M.W.J. Prins, R. Jansen, and H. van Kempen, Phys. Rev. B 53, 8105 (1996).CrossRefGoogle Scholar
  11. 11.
    Y. Suzuki, W. Nabhan, and K. Tanaka, Appl. Phys. Lett. 71, 3153 (1997).CrossRefGoogle Scholar
  12. 12.
    H. Kodama, T. Uzumaki, M. Oshiki, K. Sueoka, and K. Mukasa, J. Appl. Phys. 83, 6831 (1998).CrossRefGoogle Scholar
  13. 13.
    M.W.J. Prins, R.H.M. Groeneveld, D.L. Abraham, H. van Kempen, and H.W. van Kersteren, Appl. Phys. Lett. 66, 1141 (1995).CrossRefGoogle Scholar
  14. 14.
    Y. Suzuki, W. Nabhan, R. Shinohara, K. Yamaguchi, and T. Katayama, J. Magn. Magn. Mater. 198–199, 540 (1999).CrossRefGoogle Scholar
  15. 15.
    M. Bode, M. Getzlaff, and R. Wiesendanger, Phys. Rev. Lett. 81, 4256 (1998).CrossRefGoogle Scholar
  16. 16.
    W. Wulfhekel and J. Kirschner, Appl. Phys. Lett. 75, 1944 (1999).CrossRefGoogle Scholar
  17. 17.
    J.S. Moodera, and G. Mathon, J. Magn. Magn. Mater. 200, 248 (1999).CrossRefGoogle Scholar
  18. 18.
    Magnetic wires were kindly provided by M. Vazquez.Google Scholar
  19. 19.
    J. Velazquez, M. Vazquez, D.-X. Chen, and A. Hernando, Phys. Rev. B 50, 16737 (1994).CrossRefGoogle Scholar
  20. 20.
    H. Theuss, B. Hofmann, C. Gómez-Polo, M. Vázquez, and H. Kronmüller, J. Magn. Magn. Mater. 145, 165 (1994).CrossRefGoogle Scholar
  21. 21.
    Y. Kuk and P.J. Silverman, J. Vac. Sci. Technol. A 8, 289 (1990).CrossRefGoogle Scholar
  22. 22.
    E. Kneller, Ferromagnetismus, Springer-Verlag, Berlin (1962).Google Scholar
  23. 23.
    J. Unguris, M.R. Scheinfein, R.C. Celotta, and D.T. Pierce, Appl. Phys. Lett. 55, 2553 (1989).CrossRefGoogle Scholar
  24. 24.
    A. Hubert and R. Schäfer, Magnetic Domains, Springer-Verlag, Berlin, p. 315 (1998).Google Scholar
  25. 25.
    A. Aharoni, Introduction to the Theory of Ferromagnetism, Oxford University Press, New York (1996).Google Scholar
  26. 26.
    A. Hubert and W. Rave, J. Magn. Magn. Mater. 196–197, 325 (1999).CrossRefGoogle Scholar
  27. 27.
    H.F. Ding, W. Wufhekel, and J. Kirschner, Europhys. Lett. 57, 100 (2002).CrossRefGoogle Scholar
  28. 28.
    W. Wulfhekel, H.F. Ding, and J. Kirschner, J. Appl. Phys. 87, 6475 (2000).CrossRefGoogle Scholar
  29. 29.
    H.F. Ding, W. Wulfhekel, C. Chen, and J. Kirschner, Material Science & Engeneering B 84, 96 (2001).CrossRefGoogle Scholar
  30. 30.
    A. Sakai In: T. Sakurai, Y. Watanabe (eds) Advances in Scanning Probe Microscopy, Springer, pp. 143 (1999).Google Scholar
  31. 31.
    M.B. Stearns, J. Magn. Magn. Mater. 5, 167 (1977).CrossRefGoogle Scholar
  32. 32.
    H.F. Ding, W. Wulfhekel, and J. Kirschner, J. Magn. Magn. Mater. 242–245, 47 (2002).Google Scholar
  33. 33.
    J.S. Moodera, M.E. Taylor, and R. Meservey, Phys. Rev. B 40, 11980 (1989).CrossRefGoogle Scholar
  34. 34.
    J.S. Moodera, J. Nowak, L.R. Kinder, P.M. Tedrow, R.J.M. van de Veerdonk, B.A. Smits, M. van Kampen, H.J.M. Swagten, and W.J.M. de Jonge, Phys. Rev. Lett. 83, 3029 (1999).CrossRefGoogle Scholar
  35. 35.
    J.J. Sun and P.P. Freitas, J. Appl. Phys. 85, 5264 (1999).CrossRefGoogle Scholar
  36. 36.
    P. LeClair, H.J.M. Swagten, J.T. Kohlhepp, R.J.M. van de Veerdonk, W.J.M. de Jonge, Phys. Rev. Lett. 84, 2933 (2000).CrossRefGoogle Scholar
  37. 37.
    A. Vedyayev, N. Ryzhanova, C. Lacroix, L. Giacomoni, and B. Dieny, Europhys. Lett. 39, 219 (1997).CrossRefGoogle Scholar
  38. 38.
    W.S. Zhang, B.Z. Li, and Y. Li, Phys. Rev. B 58, 14959 (1998).CrossRefGoogle Scholar
  39. 39.
    S. Zhang, P.M. Levy, Phys. Rev. Lett. 81, 5660 (1998).CrossRefGoogle Scholar
  40. 40.
    J. Mathon and A. Umerski, Phys. Rev. B 60, 1117 (1999).CrossRefGoogle Scholar
  41. 41.
    M.K. Weilmeier, W.H. Rippard, and R.A. Buhrman, Phys. Rev. B 59, R2521 (1999).CrossRefGoogle Scholar

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© Springer-Verlag Berlin Heidelberg 2005

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  • W. Wulfhekel

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