Abstract
The quest for ultrafast magnetic processes has triggered a new field of research—femtomagnetism: using femtosecond laser pulses to demagnetize ferromagnetic metallic thin films. Despite being the subject of intense research for over a decade, the underlying mechanisms that govern the demagnetization remain unclear. Here, we investigate how an ultrashort laser pulse couples to the spin of electrons in ferromagnetic metals. It is shown that a single 50-fs laser pulse couples efficiently to a ferromagnetic film during its own propagation. This result indicates that the material polarization induced by the photon field interacts coherently with the spins. The corresponding mechanism has its origin in relativistic quantum electrodynamics, beyond the spin–orbit interaction involving the ionic potential. In addition, this coherent interaction is clearly distinguished from the incoherent ultrafast demagnetization associated with the thermalization of the spins. We forecast that the corresponding coherent self-induced processes are the dawn of a new era for future research in magnetism.
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Change history
16 June 2009
In the version of this article originally published online, corrections were needed to: Fig. 1, right-hand Gel label should read Gsl; Fig. 2b,c, the 0 label on the x axes should read 1; Fig. 3a,c, the legend for the red line should read 0°. These corrections have now been made in all versions of the article.
References
Beaurepaire, E., Merle, J.-C., Daunois, A. & Bigot, J.-Y. Ultrafast spin dynamics in ferromagnetic nickel. Phys. Rev. Lett. 76, 4250–4253 (1996).
Hohlfeld, J., Matthias, E., Knorren, R. & Bennemann, K. H. Nonequilibrium magnetization dynamics of nickel. Phys. Rev. Lett. 78, 4861–4864 (1997).
Aeschlimann, M. et al. Ultrafast spin-dependent electron dynamics in fcc Co. Phys. Rev. Lett. 79, 5158–5161 (1997).
Scholl, A., Baumgarten, L., Jacquemin, R. & Eberhardt, W. Ultrafast spin dynamics of ferromagnetic thin films observed by fs spin-resolved two-photon photoemission. Phys. Rev. Lett. 79, 5146–5149 (1997).
Hübner, W. & Zhang, G. P. Ultrafast spin dynamics in nickel. Phys. Rev. B 58, R5920–R5923 (1998).
Ganping, Ju. et al. Ultrafast time resolved photoinduced magnetization rotation in a ferromagnetic/ antiferromagnetic exchange coupled system. Phys. Rev. Lett. 82, 3705–3708 (1999).
van Kampen, M. et al. All-optical probe of coherent spin waves. Phys. Rev. Lett. 88, 227201(4) (2002).
Vomir, M., Andrade, L. H. F., Guidoni, L., Beaurepaire, E. & Bigot, J.-Y. Real space trajectory of the ultrafast magnetization dynamics in ferromagnetic metals. Phys. Rev. Lett. 94, 237601(4) (2005).
Bigot, J.-Y., Vomir, M., Andrade, L. H. F. & Beaurepaire, E. Ultrafast magnetization dynamics in ferromagnetic cobalt: The role of the anisotropy. Chem. Phys. 318, 137–146 (2005).
Bigot, J.-Y. Femtosecond magneto-optical processes in metals. C. R. Acad. Sci. Ser. IV 2, 1483–1504 (2001).
Knorren, R., Bennemann, K. H., Burgermeister, R. & Aeschlimann, M. Dynamics of excited electrons in copper and ferromagnetic transition metals: Theory and experiment. Phys. Rev. B 61, 9427–9440 (2000).
Güdde, J., Conrad, U., Jähnke, V., Hohlfeld, J. & Matthias, E. Magnetization dynamics of Ni and Co films on Cu(001) and of bulk nickel surfaces. Phys. Rev. B 59, R6608–R6611 (1999).
Regensburger, H., Vollmer, R. & Kirschner, J. Time-resolved magnetization-induced second-harmonic generation from the Ni(110) surface. Phys. Rev. B 61, 14716–14722 (2000).
Ney, O., Trzeciecki, M. & Hübner, W. Femtosecond dynamics of spin-dependent SHG response from NiO (001). Appl. Phys. B 74, 741–744 (2002).
Stamm, C. et al. Femtosecond modification of electron localization and transfer of angular momentum in nickel. Nature Mater. 6, 740–743 (2007).
Koopmans, B., Kampen, M., van, Kohlhepp, J. T. & de Jonge, W. J. M. Ultrafast magneto-optics in nickel: Magnetism or optics? Phys. Rev. Lett. 85, 844–847 (2000).
Rebei, A. & Hohlfeld, J. The magneto-optical Barnett effect: Circularly polarized light induced femtosecond magnetization reversal. Phys. Lett. A 372, 1915–1918 (2008).
Zhang, G. P. & Hübner, W. Laser-induced ultrafast demagnetization in ferromagnetic metals. Phys. Rev. Lett. 85, 3025–3028 (2000).
Zhang, G., Hübner, W., Beaurepaire, E. & Bigot, J.-Y. in Spin Dynamics in Confined Magnetic Structures I (eds Hillebrands, B. & Ounadjela, K.) 245–288 (Topics in Applied Physics, Vol. 83, Springer, 2002).
Koopmans, B., Ruigrok, J. J. M., Dalla Longa, F. & de Jonge, W. J. M. Unifying ultrafast magnetization dynamics. Phys. Rev. Lett. 95, 267207(4) (2005).
Koopmans, B. Spin dynamics: The ultimate view. Nature Mater. 6, 715–716 (2007).
Lisowski, M. et al. Femtosecond electron and spin dynamics in Gd(0001) studied by time-resolved photoemission and magneto-optics. Phys. Rev. Lett. 95, 137402(4) (2005).
Rhie, H.-S., Dürr, H. A. & Eberhardt, W. Femtosecond electron and spin dynamics in Ni/W(110) films. Phys. Rev. Lett. 90, 247201(4) (2003).
Schmidt, A. B., Pickel, M., Wiemhöfer, M., Donath, M. & Weinelt, M. Spin-dependent electron dynamics in front of a ferromagnetic surface. Phys. Rev. Lett. 95, 107402(4) (2005).
Beaurepaire, E. et al. Coherent terahertz emission from ferromagnetic films excited by femtosecond laser pulses. Appl. Phys. Lett. 84, 3465–3467 (2004).
Hilton, D. J. et al. Terahertz emission via ultrashort-pulse excitation of magnetic metal films. Opt. Lett. 29/15, 1805–1807 (2004).
Guidoni, L., Beaurepaire, E. & Bigot, J.-Y. Magneto-optics in the ultrafast regime: Thermalization of spin populations in ferromagnetic films. Phys. Rev. Lett. 89, 17401(4) (2002).
Oppeneer, P. M. & Liebsch, A. Ultrafast demagnetization in Ni: Theory of magneto-optics for non-equilibrium electron distributions. J. Phys. Condens. Matter 16, 5519–5530 (2004).
Walowski, J. et al. Energy equilibration processes of electrons, magnons, and phonons at the femtosecond time scale. Phys. Rev. Lett. 101, 237401(4) (2008).
Radu, I. et al. Laser-induced magnetization dynamics of lanthanide-doped permalloy thin films. Phys. Rev. Lett. 102, 117201 (2009).
Carpene, E. et al. Dynamics of electron–magnon interaction and ultrafast demagnetization in thin iron films. Phys. Rev. B 78, 174422(6) (2008).
Bigot, J.-Y. Irsee International Colloquium of the SPP1133—Ultrafast Magnetization Processes, Kloster Irsee, 15–19 Sept. 89 (Technische Universität Kaiserslautern and Deutsche Forschungsgemeinschaft, 2008).
Beaurepaire, E. et al. Spin dynamics in CoPt3 alloy films: A magnetic phase transition in the femtosecond time scale. Phys. Rev. B 58, 12134–12137 (1998).
Chubykalo-Fesenko, O., Nowak, U., Chantrell, R. W. & Garanin, D. Dynamic approach for micromagnetics close to the Curie temperature. Phys. Rev. B 74, 094436(5) (2006).
Dodge, J. S. et al. Time-resolved optical observation of spin-wave dynamics. Phys. Rev. Lett. 83, 4650–4653 (1999).
Miltat, J., Albuquerque, G. & Thiaville, A. in Spin Dynamics in Confined Magnetic Structures, Vol. I (eds Hillebrands, B. & Ounadjela, K.) 1–31 (Topics in Applied Physics, Vol. 83, Springer, 2002).
Ralph, D. C. & Stiles, M. D. Spin transfer torques. J. Magn. Magn. Mater. 320, 1190–1216 (2008).
Argyres, P. N. Theory of the Faraday and Kerr effects in ferromagnetics. Phys. Rev. 97, 334–345 (1955).
Strange, P. Relativistic Quantum Mechanics Ch. 7 (Cambridge Univ. Press, 1998).
Zhang, G. P. Laser-induced orbital and spin excitations in ferromagnets: Insights from a two-level system. Phys. Rev. Lett. 101, 187203(4) (2008).
Halilov, S. V., Eschrig, H., Perlov, A. Y. & Oppeneer, P. M. Adiabatic spin dynamics from spin-density-functional theory: Application to Fe, Co, and Ni. Phys. Rev. B 58, 293–302 (1998).
Brito-Cruz, C.-H., Gordon, J.-P., Becker, P. C., Fork, R. L. & Shank, C. V. IEEE J. Quantum Electron. 24, 261–269 (1988).
Bigot, J.-Y., Portella, M. T., Schoenlein, R. W., Cunningham, J. E. & Shank, C. V. Two-dimensional carrier–carrier screening in a quantum well. Phys. Rev. Lett. 67, 636–639 (1991).
El Sayed, K., Banyai, L. & Haug, H. Coulomb quantum kinetic and optical dephasing on the femtosecond time scale. Phys. Rev. B 50, 1541–1550 (1994).
Bonitz, M. et al. Theory and simulation of strong correlations in quantum Coulomb systems. J. Phys. A 36, 5921–5930 (2003).
Pershan, P. S., van der Ziel, J. P. & Malmstrom, L. D. Theoretical discussion of the inverse Faraday effect, Raman scattering and related phenomena. Phys. Rev. 143, 574–583 (1965).
Kimel, A. V. et al. Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses. Nature 435, 655–657 (2005).
Hansteen, F., Kimel, A., Kirilyuk, A. & Rasing, Th. Femtosecond photomagnetic switching of spins in ferrimagnetic garnet films. Phys. Rev. Lett. 95, 047402(4) (2005).
Stanciu, C. D. et al. Ultrafast interaction of the angular momentum of photons with spins in the metallic amorphous alloy GdFeCo. Phys. Rev. Lett. 98, 207401(4) (2007).
Kurkin, M. I., Bakulina, N. B. & Pisarev, R. V. Transient inverse Faraday effect and ultrafast optical switching of magnetization. Phys. Rev. B 78, 134430(9) (2008).
Chovan, J., Kavousanaki, E. G. & Perakis, I. E. Ultrafast light-induced magnetization dynamics of ferromagnetic semiconductors. Phys. Rev. Lett. 96, 057402(4) (2006).
Acknowledgements
We thank I. Perakis for helpful discussions on coherent magnetic effects in semiconductors, and J. Arabski and M. Albrecht for their technical support. This project was carried on thanks to the financial support of the Centre National de la Recherche Scientifique in France.
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J.Y.B. and M.V. designed and carried out the experiments, analysed the data and wrote the paper. E.B. supervised the samples elaboration and characterization.
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Bigot, JY., Vomir, M. & Beaurepaire, E. Coherent ultrafast magnetism induced by femtosecond laser pulses. Nature Phys 5, 515–520 (2009). https://doi.org/10.1038/nphys1285
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DOI: https://doi.org/10.1038/nphys1285
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