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Experimental observation of the optical spin transfer torque


The spin transfer torque is a phenomenon in which angular momentum of a spin polarized electrical current entering a ferromagnet is transferred to the magnetization. The effect has opened a new research field of electrically driven magnetization dynamics in magnetic nanostructures and plays an important role in the development of a new generation of memory devices and tunable oscillators. Optical excitations of magnetic systems by laser pulses have been a separate research field the aim of which is to explore magnetization dynamics at short timescales and enable ultrafast spintronic devices. We report the experimental observation of the optical spin transfer torque, predicted theoretically several years ago, building the bridge between these two fields of spintronics research. In a pump-and-probe optical experiment we measure coherent spin precession in a (Ga, Mn)As ferromagnetic semiconductor excited by circularly polarized laser pulses. During the pump pulse, the spin angular momentum of photo-carriers generated by the absorbed light is transferred to the collective magnetization of the ferromagnet. We analyse quantitatively the observed magnetization dynamics triggered by the optical spin transfer torque using independently determined micromagnetic parameters and magneto-optical coefficients of the studied (Ga, Mn)As.

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Figure 1: Schematic illustration of the optical spin transfer torque.
Figure 2: Experimental observation of the optical spin transfer torque.
Figure 3: Absence of inverse magneto-optical effect and polarization-independent excitations.
Figure 4: Helicity-dependent and polarization-independent signals at different piezovoltages.


  1. Fernández-Rossier, J., Núñez, A. S., Abolfath, M. & MacDonald, A. H. Optical spin transfer in ferromagnetic semiconductors. Preprint at (2003).

  2. 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 

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

    Article  ADS  Google Scholar 

  4. Wang, D. M. 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 

  5. 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 

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

    Article  ADS  Google Scholar 

  7. 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 

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

    Article  ADS  Google Scholar 

  9. 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 

  10. 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 

  11. 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 

  12. 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 

  13. Zutic, I., Fabian, J. & Erwin, S. C. Spin injection and detection in silicon. Phys. Rev. Lett. 97, 026602 (2006).

    Article  ADS  Google Scholar 

  14. Burch, K. S., Stephens, J., Kawakami, R. K., Awschalom, D. D. & Basov, D. N. Ellipsometric study of the electronic structure of GaMnAs and low-temperature GaAs. Phys. Rev. B 70, 205208 (2004).

    Article  ADS  Google Scholar 

  15. Vanhaverbeke, A. & Viret, M. Simple model of current-induced spin torque in domain walls. Phys. Rev. B 75, 024411 (2007).

    Article  ADS  Google Scholar 

  16. Kimel, A. V. et al. Observation of giant magnetic linear dichroism in (Ga, Mn)As. Phys. Rev. Lett. 94, 227203 (2005).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  18. Jungwirth, T. et al. Systematic study of Mn-doping trends in optical properties of (Ga, Mn)As. Phys. Rev. Lett. 105, 227201 (2010).

    Article  ADS  Google Scholar 

  19. Rushforth, A. W. et al. Voltage control of magnetocrystalline anisotropy in ferromagnetic–semiconductor/piezoelectric hybrid structures. Phys. Rev. B 78, 085314 (2008).

    Article  ADS  Google Scholar 

  20. De Ranieri, E. et al. Lithographically and electrically controlled strain effects on anisotropic magnetoresistance in (Ga, Mn)As. New J. Phys. 10, 065003 (2008).

    Article  Google Scholar 

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We acknowledge fruitful discussions with A. V. Kimel, J. Sinova, J. Wunderlich, J. Fernández-Rossier and A. H. MacDonald, and support from the European Union European Research Council (ERC) Advanced Grant No. 268066 and FP7-215368 SemiSpinNet, from the Ministry of Education of the Czech Republic Grants No. LC510 and MSM0021620834, from the Grant Agency of the Czech Republic Grant No. 202/09/H041 and P204/12/0853, from the Charles University in Prague Grant No. SVV-2012-265306 and 443011, and from the Academy of Sciences of the Czech Republic No. AV0Z10100521 and Preamium Academiae.

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Sample preparation: V.N., M.C., E.R. and E.D.R.; experiments and data analysis: E.R., N.T., P.N., P.M., K.O and T.J.; data modelling: P.N. and F.T.; theory: J.Z. and T.J.; writing: T.J. and P.N.; project planning: P.N. and T.J.

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Correspondence to P. Němec.

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The authors declare no competing financial interests.

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

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