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.

  • Article
  • Published:

Experimental observation of the optical spin–orbit torque

Nature Photonics volume 7, pages 492–498 (2013)Cite this article

Subjects

Abstract

Electrical and optical control of magnetization are of central importance in the research and applications of spintronics. Non-relativistic angular momentum transfer or relativistic spin–orbit coupling provide efficient means by which electrical current driven through a ferromagnet can exert a torque on the magnetization. Ferromagnetic semiconductors like (Ga,Mn)As are suitable model systems with which to search for optical counterparts of these phenomena, where photocarriers excited by a laser pulse exert torque upon magnetization. Here, we report the observation of an optical spin–orbit torque (OSOT) in (Ga,Mn)As. The phenomenon originates from spin–orbit coupling of non-equilibrium photocarriers excitated by helicity-independent pump laser pulses, which do not impart angular momentum. In our measurements of the time-dependent magnetization trajectories, the signatures of OSOT are clearly distinct from the competing thermal excitation mechanism, and OSOT can even dominate in (Ga,Mn)As materials with appropriately controlled micromagnetic parameters.

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

Figure 1: Schematic illustration and experimental observation of OSOT.
Figure 2: Direct experimental reconstruction of the magnetization trajectory from MO signals.
Figure 3: Characterization of 3% Mn-doped (Ga,Mn)As.
Figure 4: Suppression of the damping and thermal excitation mechanism by magnetic field.
Figure 5: Suppression of the thermal excitation mechanism at higher Mn dopings.

Similar content being viewed by others

References

  1. Berger, L. Exchange interaction between ferromagnetic domain wall and electric current in very thin metallic films. J. Appl. Phys. 55, 1954–1956 (1984).

    Article  ADS  Google Scholar 

  2. Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996).

    Article  ADS  Google Scholar 

  3. Berger, L. Emission of spin waves by a magnetic multilayer traversed by a current. Phys. Rev. B 54, 9353–9358 (1996).

    Article  ADS  Google Scholar 

  4. Chappert, C., Fert, A. & Dau, F. N. V. The emergence of spin electronics in data storage. Nature Mater. 6, 813–823 (2007).

    Article  ADS  Google Scholar 

  5. Ralph, D. & Stiles, M. Spin transfer torques. J. Magn. Magn. Mater. 320, 1190–1216 (2008).

    Article  ADS  Google Scholar 

  6. Brataas, A., Kent, A. D. & Ohno, H. Current-induced torques in magnetic materials. Nature Mater. 11, 372–381 (2012).

    Article  ADS  Google Scholar 

  7. Němec, P. et al. Experimental observation of the optical spin transfer torque. Nature Phys. 8, 411–415 (2012).

    Article  ADS  Google Scholar 

  8. Fernández-Rossier, J., Núñez, A. S., Abolfath, M. & MacDonald, A. H. Optical spin transfer in ferromagnetic semiconductors. Preprint at http://lanl.arXiv.org/abs/cond-mat/0304492 (2003).

  9. Núñez, A. S., Fernández-Rossier, J., Abolfath, M. & MacDonald, A. H. Optical control of the magnetization damping in ferromagnetic semiconductors. J. Magn. Magn. Mater. 272–276, 1913–1914 (2004).

    Article  ADS  Google Scholar 

  10. Manchon, A. & Zhang, S. Theory of nonequilibrium intrinsic spin torque in a single nanomagnet. Phys. Rev. B 78, 212405 (2008).

    Article  ADS  Google Scholar 

  11. Manchon, A. & Zhang, S. Theory of spin torque due to spin–orbit coupling. Phys. Rev. B 79, 094422 (2009).

    Article  ADS  Google Scholar 

  12. Garate, I. & MacDonald, A. H. Influence of a transport current on magnetic anisotropy in gyrotropic ferromagnets. Phys. Rev. B 80, 134403 (2010).

    Article  ADS  Google Scholar 

  13. Chernyshov, A. et al. Evidence for reversible control of magnetization in a ferromagnetic material by means of spin–orbit magnetic field. Nature Phys. 5, 656–659 (2009).

    Article  ADS  Google Scholar 

  14. Miron, I. M. et al. Current-driven spin torque induced by the Rashba effect in a ferromagnetic metal layer. Nature Mater. 9, 230–234 (2010).

    Article  ADS  Google Scholar 

  15. Fang, D. et al. Spin–orbit driven ferromagnetic resonance: a nanoscale magnetic characterization technique. Nature Nanotech. 6, 413–417 (2011).

    Article  ADS  Google Scholar 

  16. Jungwirth, T., Sinova, J., Mašek, J., Kučera, J. & MacDonald, A. H. Theory of ferromagnetic (III,Mn)V semiconductors. Rev. Mod. Phys. 78, 809–864 (2006).

    Article  ADS  Google Scholar 

  17. Oiwa, A., Takechi, H. & Munekata, H. Photoinduced magnetization rotation and precessional motion of magnetization in ferromagnetic (Ga,Mn)As. J. Supercond. Nov. Magn. 18, 9–13 (2005).

    Article  ADS  Google Scholar 

  18. Wang, D. M. et al. Light-induced magnetic precession in (Ga,Mn)As slabs: hybrid standing-wave Damon–Eshbach modes. Phys. Rev. B 75, 233308 (2007).

    Article  ADS  Google Scholar 

  19. Takechi, H., Oiwa, A., Nomura, K., Kondo, T. & Munekata, H. Light-induced precession of ferromagnetically coupled Mn spins in ferromagnetic (Ga,Mn)As. Phys. Status Solidi C 3, 4267–4270 (2007).

    Article  ADS  Google Scholar 

  20. Qi, J. et al. Coherent magnetization precession in GaMnAs induced by ultrafast optical excitation. Appl. Phys. Lett. 91, 112506 (2007).

    Article  ADS  Google Scholar 

  21. Qi, J. et al. Ultrafast laser-induced coherent spin dynamics in ferromagnetic Ga1–xMnxAs/GaAs structures. Phys. Rev. B 79, 085304 (2009).

    Article  ADS  Google Scholar 

  22. Rozkotová, E. et al. Light-induced magnetization precession in GaMnAs. Appl. Phys. Lett. 92, 122507 (2008).

    Article  ADS  Google Scholar 

  23. Rozkotová, E. et al. Coherent control of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As. Appl. Phys. Lett. 93, 232505 (2008).

    Article  ADS  Google Scholar 

  24. Hashimoto, Y. & Munekata, H. Coherent manipulation of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As with successive optical pumping. Appl. Phys. Lett. 93, 202506 (2008).

    Article  ADS  Google Scholar 

  25. Hashimoto, Y., Kobayashi, S. & Munekata, H. Photoinduced precession of magnetization in ferromagnetic (Ga,Mn)As. Phys. Rev. Lett. 100, 067202 (2008).

    Article  ADS  Google Scholar 

  26. Kobayashi, S., Suda, K., Aoyama, J., Nakahara, D. & Munekata, H. Photo-induced precession of magnetization in metal/(Ga,Mn)As systems. IEEE Trans. Magn. 46, 2470–2473 (2010).

    Article  ADS  Google Scholar 

  27. Yildirim, M. et al. Interband dephasing and photon echo response in gamnas. Appl. Phys. Lett. 101, 062403 (2012).

    Article  ADS  Google Scholar 

  28. Wang, J. et al. Ultrafast magneto-optics in ferromagnetic III–V semiconductors. J. Phys. Condens. Matter 18, R501–R530 (2006).

    Article  Google Scholar 

  29. Kirilyuk, A., Kimel, A. V. & Rasing, T. Ultrafast optical manipulation of magnetic order. Rev. Mod. Phys. 82, 2731–2784 (2010).

    Article  ADS  Google Scholar 

  30. Tesařová, N. et al. Direct measurement of the three dimensional magnetization vector trajectory in GaMnAs by a magneto-optical pump-and-probe method. Appl. Phys. Lett. 100, 102403 (2012).

    Article  ADS  Google Scholar 

  31. Němec, P. et al. The essential role of carefully optimized synthesis for elucidating intrinsic material properties of (Ga,Mn)As. Nature Commun. 4, 1422 (2013).

    Article  ADS  Google Scholar 

  32. Zemen, J., Kučera, J., Olejník, K. & Jungwirth, T. Magneto crystalline anisotropies in (Ga,Mn)As: a systematic theoretical study and comparison with experiment. Phys. Rev. B 80, 155203 (2009).

    Article  ADS  Google Scholar 

  33. Gray, A. X. et al. Bulk electronic structure of the dilute magnetic semiconductor GaMnAs through hard X-ray angle-resolved photoemission. Nature Mater. 11, 957–962 (2012).

    Article  ADS  Google Scholar 

  34. Ohya, S., Takata, K. & Tanaka, M. Nearly non-magnetic valence band of the ferromagnetic semiconductor GaMnAs. Nature Phys. 7, 342–347 (2011).

    Article  ADS  Google Scholar 

  35. Chiba, D. et al. Magnetization vector manipulation by electric fields. Nature 455, 515–518 (2008).

    Article  ADS  Google Scholar 

  36. Owen, M. H. S. et al. Low voltage control of ferromagnetism in a semiconductor p–n junction. New J. Phys. 11, 023008 (2009).

    Article  ADS  Google Scholar 

  37. Ganichev, S. D. et al. Zero-bias spin separation. Nature Phys. 2, 609–613 (2006).

    Article  ADS  Google Scholar 

  38. Tarasenko, S. A. Optical orientation of electron spins by linearly polarized light. Phys. Rev. B 72, 113302 (2005).

    Article  ADS  Google Scholar 

  39. Jungwirth, T. et al. Demonstration of molecular beam epitaxy and a semiconducting band structure for I–Mn–V compounds. Phys. Rev. B 83, 035321 (2011).

    Article  ADS  Google Scholar 

  40. Park, B. G. et al. A spin-valve-like magnetoresistance of an antiferromagnet-based tunnel junction. Nature Mater. 10, 347–351 (2011).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

The authors acknowledge discussions with A.H. MacDonald, J. Sinova and J. Wunderlich, and support from the European Research Council (advanced grant no. 268066), Framework Programme 7 (grant no. 215368), the Engineering and Physical Sciences Research Council (grant no. EP/H029257/1), the Ministry of Education of the Czech Republic (grant no. LM2011026), the Grant Agency of the Czech Republic (grant nos. 202/09/H041 and P204/12/0853), the Charles University in Prague (grant nos. SVV-2012-265306 and 443011) and the Academy of Sciences of the Czech Republic Praemium Academiae.

Author information

Authors and Affiliations

  1. Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague 2, Czech Republic

    N. Tesařová, P. Němec, E. Rozkotová, T. Janda, D. Butkovičová, F. Trojánek & P. Malý

  2. School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK

    J. Zemen & T. Jungwirth

  3. Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic.

    J. Zemen, K. Olejník, V. Novák & T. Jungwirth

Authors
  1. N. Tesařová
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. P. Němec
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. E. Rozkotová
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. J. Zemen
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. T. Janda
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. D. Butkovičová
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. F. Trojánek
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. K. Olejník
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. V. Novák
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. P. Malý
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. T. Jungwirth
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

V.N. and K.O. prepared the samples. N.T., P.N., E.R., T.Ja., D.B., P.M., K.O. and T.Ju. conducted the experiments and analysed the measured data. P.N. and F.T. performed data modelling. J.Z. and T.Ju. developed the microscopic theory and performed the calculations. P.N. and T.Ju wrote the manuscript.

Corresponding author

Correspondence to P. Němec.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 3745 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Tesařová, N., Němec, P., Rozkotová, E. et al. Experimental observation of the optical spin–orbit torque. Nature Photon 7, 492–498 (2013). https://doi.org/10.1038/nphoton.2013.76

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphoton.2013.76

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