When a magnetic film is excited by a femtosecond laser pulse, either with THz or with optical frequencies, then there is at least a partial demagnetization within a few hundred femtoseconds, followed by a remagnetization to the original state on a bit longer time scale. This phenomenon is caused by a complex interaction of light with quantum matter. This paper gives a review of the present knowledge of the underlying physics. It discusses first the situation of a direct change of the magnetization by its interaction with the electromagnetic wave of the laser pulse, which appears during THz laser pulses with small field amplitudes. Then it considers the situation of an indirect change which appears after THz laser pulses with large field amplitudes and after optical laser pulses. In these cases the laser photons primarily excite electrons, with subsequent modifications of their spin-angular momenta by spin-flip scatterings of these electrons at quasiparticles, either at other electrons or at phonons or at magnons. The contributions of these various spin-flip scatterings to demagnetization are investigated. Then the transfer of angular momentum from the electronic spin system to the lattice during ultrafast demagnetization is discussed by describing the lattice vibrations in terms of magnetoelastic spin-phonon modes. Finally, the effect of electronic correlations in the sense of the density-matrix theory is investigated.
| Published in | American Journal of Modern Physics (Volume 7, Issue 2) |
| DOI | 10.11648/j.ajmp.20180702.12 |
| Page(s) | 68-74 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2018. Published by Science Publishing Group |
Ultrafast Demagnetization, Femtosecond Laser Pulses, THz and Optical Frequencies, Magnetization Precession, Spin-Flip Scatterings of Electrons, Angular Momentum Transfer, Electronic Correlations
| [1] | B. Koopmans, G. Malinowski, F. Dalla Longa, D. Steiauf, M. Fähnle, T. Roth, M. Cinchetti, and M. Aeschlimann, "Explaining the paradoxial diversity of ultrafast laser-induced demagnetization", Nat. Mater. 9, 259–265 (2010). |
| [2] | A. Kirilyuk, A. V. Kimel, and T. Rasing, "Ultrafast optical manipulation of magnetic order", Rev. Mod. Phys. 82, 2731-2784 (2010). |
| [3] | E. Beaurepaire, J.-C. Merle, A. Daunois, and J.-Y. Bigot, "Ultrafast Spin Dynamics in Ferromagnetic Nickel", Phys. Rev. Lett. 76, 4250-4253 (1996). |
| [4] | M. Battiato, K. Carva, and P. Oppeneer, "Super-Diffusive Spin Transport as a Mechanism for Ultrafast Demagnetization", Phys. Rev. Lett. 105, 027203-027206 (2010). |
| [5] | M. Shalaby, C. Vicario, and C. P. Hauri, "Low frequency terahertz-induced demagnetization in ferromagnetic Nickel", Appl. Phys. Lett. 108, 162903-162906 (2016). |
| [6] | Y. Yafet, "g Factors and Spin-Lattice Relaxation of Conduction Electrons", in Solid State Physics, Vol. 14, edited by F. Seitz and D. Turnbull (Academic, New York), 1 ff (1963). |
| [7] | B. Y. Mueller, A. Baral, S. Vollmar, M. Cinchetti, M. Aeschlimann, H. C. Schneider, and B. Rethfeld, "Feedback Effect during Ultrafast Demagnetization Dynamics in Ferromagnets", Phys. Rev. Lett. 111, 167204-167208 (2013). |
| [8] | B. Y. Mueller, M. Haag, and M. Fähnle, "Ab-initio theory for ultrafast magnetization dynamics with a dynamic band structure", J. Magn. Magn. Mater. 414, 14-18 (2016). |
| [9] | C. Illg, M. Haag, and M. Fähnle, "Ultrafast demagnetization after laser irradiation in transition metals: Ab-initio calculations of the spin-flip electron-phonon scattering with reduced exchange splitting", Phys. Rev. B 88, 214404-1–214404-10 (2013). |
| [10] | L. Nordheim, "Zur Elektronentheorie der Metalle", Ann. Phys. 401, 607-640 (1931). |
| [11] | C. Illg, B. Meyer, and M. Fähnle, "Frequencies and polarization vectors of phonons: Results from force constants which are fitted to experimental data or calculated ab initio", Phys. Rev. B 86, 174309-1-174314-6 (2012). |
| [12] | C. Ederer, "Theorie magneto-optischer Effekte im Röntgenbereich und Anwendung auf niedrigdimensionale Systeme", PhD thesis, Max Planck Institute for Metals Research and University of Stuttgart (2003). |
| [13] | O. K. Andersen and O. Jepsen, "Explicit First-Principles Tight-Binding Theory", Phys. Rev. Lett. 53, 2571–2574 (1984). |
| [14] | Y. P. Perdew, and Y. Wang, "Accurate and simple density functional for the electronic exchange energy, Generalized Gradient Approximation", Phys. Rev. B 33, 8800 – 8802 (1986). |
| [15] | Y. P. Perdew, and Y. Wang, "Accurate and simple analytic representation of the electron-gas correlation energy", Phys. Rev. B 45, 13244 – 13249 (1992). |
| [16] | M. Haag, C. Illg, and M. Fähnle, "Theory of scatterings of crystal electrons at magnons", Phys. Rev. B 87, 214427– 1–214434-8 (2013). |
| [17] | O. Grotheer, 2002, "Ab-initio Berechnungen der Spinwellenspektren von Eisen, Kobalt und Nickel", PhD thesis, Max Planck Institute for Metals Research and University of Stuttgart (2002). |
| [18] | E. Carpene, E. Mancini, C. Dallera, K. Brenna, E. Puppin, and S. De Silvestri, "Dynamics of electron-magnon interaction and ultrafast demagnetization in thin iron films”, Phys. Rev. B 78, 174422–1–174422–6 (2008). |
| [19] | M. Haag, C. Illg, and M. Fähnle, "Role of electron-magnon scatterings in ultrafast demagnetization", Phys. Rev. B 90, 014417–1-014417-6 (2014). |
| [20] | A. Manchon, Q. Li, L. Xu, and S. Zhang, "Theory of laser-induced demagnetization at high temperatures", Phys. Rev. B 85, 064408-1-064416–9 (2012). |
| [21] | A. J. Schellekens and B. Koopmans, "Comparing Ultrafast Demagnetization Rates Between Competing Models for Finite Temperature Magnetism", Phys. Rev. Lett. 110, 214204-214208 (2013). |
| [22] | T. Tsatsoulis, C. Illg, M. Haag, B. Y. Mueller, L. Zhang, and M. Fähnle, “Ultrafast demagnetization after femtosecond laser pulses: Transfer of angular momentum from the electron system to magnetoelastic spin-phonon modes”, Phys. Rev. B 93, 134411–1–134417-7 (2016). |
| [23] | L. Zhang and Q. Niu, “Angular momentum of phonons and the Einstein-de Haas effect”, Phys. Rev. Letters 112, 085503-085507 (2014). |
| [24] | M. Joschko, M. Woerner, T. Elsaesser, E. Binder, T. Kuhn, R. Hey, H. Kostial, and K. Ploog, "Heavy-Light Hole Quantum Beats in the Band-to-Band Continuum of GaAs observed in 20 Femtosecond Pump-Probe Experiments", Phys. Rev. Lett. 78, 737-740 (1997). |
| [25] | W. Weng, J. Briones, N. Teeny, B. Y. Mueller, M. Haag, T. Kuhn, and M. Fähnle, "Unexpectedly marginal effect of electronic correlations on ultrafast demagnetization after femtosecond laser pulses", Phys. Rev. B 95, 224439–1–224443-4 (2017). |
| [26] | D. Ter Haar, "Theory and applications of the density matrix", Reports on Progress in Physics 24, 304–362 (1961). |
APA Style
Manfred Fähnle, Michael Haag, Christian Illg, Benedikt Mueller, Weikai Weng, et al. (2018). Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter. American Journal of Modern Physics, 7(2), 68-74. https://doi.org/10.11648/j.ajmp.20180702.12
ACS Style
Manfred Fähnle; Michael Haag; Christian Illg; Benedikt Mueller; Weikai Weng, et al. Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter. Am. J. Mod. Phys. 2018, 7(2), 68-74. doi: 10.11648/j.ajmp.20180702.12
AMA Style
Manfred Fähnle, Michael Haag, Christian Illg, Benedikt Mueller, Weikai Weng, et al. Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter. Am J Mod Phys. 2018;7(2):68-74. doi: 10.11648/j.ajmp.20180702.12
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author = {Manfred Fähnle and Michael Haag and Christian Illg and Benedikt Mueller and Weikai Weng and Theodoros Tsatsoulis and Haonan Huang and Johan Briones and Nicolas Teeny and Lifa Zhang and Tilmann Kuhn},
title = {Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter},
journal = {American Journal of Modern Physics},
volume = {7},
number = {2},
pages = {68-74},
doi = {10.11648/j.ajmp.20180702.12},
url = {https://doi.org/10.11648/j.ajmp.20180702.12},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajmp.20180702.12},
abstract = {When a magnetic film is excited by a femtosecond laser pulse, either with THz or with optical frequencies, then there is at least a partial demagnetization within a few hundred femtoseconds, followed by a remagnetization to the original state on a bit longer time scale. This phenomenon is caused by a complex interaction of light with quantum matter. This paper gives a review of the present knowledge of the underlying physics. It discusses first the situation of a direct change of the magnetization by its interaction with the electromagnetic wave of the laser pulse, which appears during THz laser pulses with small field amplitudes. Then it considers the situation of an indirect change which appears after THz laser pulses with large field amplitudes and after optical laser pulses. In these cases the laser photons primarily excite electrons, with subsequent modifications of their spin-angular momenta by spin-flip scatterings of these electrons at quasiparticles, either at other electrons or at phonons or at magnons. The contributions of these various spin-flip scatterings to demagnetization are investigated. Then the transfer of angular momentum from the electronic spin system to the lattice during ultrafast demagnetization is discussed by describing the lattice vibrations in terms of magnetoelastic spin-phonon modes. Finally, the effect of electronic correlations in the sense of the density-matrix theory is investigated.},
year = {2018}
}
TY - JOUR T1 - Review of Ultrafast Demagnetization After Femtosecond Laser Pulses: A Complex Interaction of Light with Quantum Matter AU - Manfred Fähnle AU - Michael Haag AU - Christian Illg AU - Benedikt Mueller AU - Weikai Weng AU - Theodoros Tsatsoulis AU - Haonan Huang AU - Johan Briones AU - Nicolas Teeny AU - Lifa Zhang AU - Tilmann Kuhn Y1 - 2018/01/18 PY - 2018 N1 - https://doi.org/10.11648/j.ajmp.20180702.12 DO - 10.11648/j.ajmp.20180702.12 T2 - American Journal of Modern Physics JF - American Journal of Modern Physics JO - American Journal of Modern Physics SP - 68 EP - 74 PB - Science Publishing Group SN - 2326-8891 UR - https://doi.org/10.11648/j.ajmp.20180702.12 AB - When a magnetic film is excited by a femtosecond laser pulse, either with THz or with optical frequencies, then there is at least a partial demagnetization within a few hundred femtoseconds, followed by a remagnetization to the original state on a bit longer time scale. This phenomenon is caused by a complex interaction of light with quantum matter. This paper gives a review of the present knowledge of the underlying physics. It discusses first the situation of a direct change of the magnetization by its interaction with the electromagnetic wave of the laser pulse, which appears during THz laser pulses with small field amplitudes. Then it considers the situation of an indirect change which appears after THz laser pulses with large field amplitudes and after optical laser pulses. In these cases the laser photons primarily excite electrons, with subsequent modifications of their spin-angular momenta by spin-flip scatterings of these electrons at quasiparticles, either at other electrons or at phonons or at magnons. The contributions of these various spin-flip scatterings to demagnetization are investigated. Then the transfer of angular momentum from the electronic spin system to the lattice during ultrafast demagnetization is discussed by describing the lattice vibrations in terms of magnetoelastic spin-phonon modes. Finally, the effect of electronic correlations in the sense of the density-matrix theory is investigated. VL - 7 IS - 2 ER -
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