Laser-induced ultrafast demagnetization in ferromagnetic metals

Physical Review Letters

Volumn 85, Issue 14, 2000, Pages 3025-3028

  Zhang, G P ^a,b   Hubner W ^a  

^a MAX PLANCK INSTITUTE OF MICROSTRUCTURE PHYSICS   (Germany)

^b UNIVERSITY OF TENNESSEE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BAND STRUCTURE; DEMAGNETIZATION; DIFFERENTIAL EQUATIONS; ELECTRON TRANSITIONS; GROUND STATE; LASER PULSES; MAGNETIC MOMENTS; MAGNETOOPTICAL EFFECTS; NICKEL; QUANTUM THEORY; SECOND HARMONIC GENERATION; ULTRAFAST PHENOMENA;

EXCITED STATE; FERROMAGNETIC NICKEL; LASER INDUCED ULTRAFAST DEMAGNETIZATION; SCHRODINGER EQUATION; SPIN ORBIT COUPLING;

FERROMAGNETIC MATERIALS;

EID: 0342918645     PISSN: 00319007     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevLett.85.3025     Document Type: Article

References (27)

1. M. K. Kryder, J. Appl. Phys. 57, 3913 (1985); A. Vaterlaus et al., Phys. Rev. Lett. 67, 3314 (1991).
2. M. K. Kryder, J. Appl. Phys. 57, 3913 (1985); A. Vaterlaus et al., Phys. Rev. Lett. 67, 3314 (1991).
3. E. Beaurepaire et al., Phys. Rev. Lett. 76, 4250 (1996).
4. J. Hohlfeld et al., Phys. Rev. Lett. 78, 4861 (1997); 79, 960(E) (1997).
5. J. Hohlfeld et al., Phys. Rev. Lett. 78, 4861 (1997); 79, 960(E) (1997).
6. M. Aeschlimann et al., Phys. Rev. Lett. 79, 5158 (1997); A. Scholl et al., Phys. Rev. Lett. 79, 5146 (1997); G. Ju et al., Phys. Rev. Lett. 82, 3705 (1999).
7. M. Aeschlimann et al., Phys. Rev. Lett. 79, 5158 (1997); A. Scholl et al., Phys. Rev. Lett. 79, 5146 (1997); G. Ju et al., Phys. Rev. Lett. 82, 3705 (1999).
8. M. Aeschlimann et al., Phys. Rev. Lett. 79, 5158 (1997); A. Scholl et al., Phys. Rev. Lett. 79, 5146 (1997); G. Ju et al., Phys. Rev. Lett. 82, 3705 (1999).
9. W. Hübner and G. P. Zhang, Phys. Rev. B 58, R5920 (1998); G. P. Zhang and W. Hübner, Appl. Phys. B 68, 495 (1999); J. Appl. Phys. 85, 5657 (1999); W. Hübner and G. P. Zhang, J. Magn. Magn. Mater. 189, 101 (1998). It is important to realize that, due to the translational invariance in solids and the SOC, the angular momentum is not a good quantum number and these original orbital multiplets are not well defined, where those multiplets are replaced by bands. The direct consequence is that, even within the same band, the optical transition is allowed.
10. W. Hübner and G. P. Zhang, Phys. Rev. B 58, R5920 (1998); G. P. Zhang and W. Hübner, Appl. Phys. B 68, 495 (1999); J. Appl. Phys. 85, 5657 (1999); W. Hübner and G. P. Zhang, J. Magn. Magn. Mater. 189, 101 (1998). It is important to realize that, due to the translational invariance in solids and the SOC, the angular momentum is not a good quantum number and these original orbital multiplets are not well defined, where those multiplets are replaced by bands. The direct consequence is that, even within the same band, the optical transition is allowed.
11. W. Hübner and G. P. Zhang, Phys. Rev. B 58, R5920 (1998); G. P. Zhang and W. Hübner, Appl. Phys. B 68, 495 (1999); J. Appl. Phys. 85, 5657 (1999); W. Hübner and G. P. Zhang, J. Magn. Magn. Mater. 189, 101 (1998). It is important to realize that, due to the translational invariance in solids and the SOC, the angular momentum is not a good quantum number and these original orbital multiplets are not well defined, where those multiplets are replaced by bands. The direct consequence is that, even within the same band, the optical transition is allowed.
12. W. Hübner and G. P. Zhang, Phys. Rev. B 58, R5920 (1998); G. P. Zhang and W. Hübner, Appl. Phys. B 68, 495 (1999); J. Appl. Phys. 85, 5657 (1999); W. Hübner and G. P. Zhang, J. Magn. Magn. Mater. 189, 101 (1998). It is important to realize that, due to the translational invariance in solids and the SOC, the angular momentum is not a good quantum number and these original orbital multiplets are not well defined, where those multiplets are replaced by bands. The direct consequence is that, even within the same band, the optical transition is allowed.
13. J. Güdde et al., Phys. Rev. B 59, R6608 (1999). Although their time scale is already much shorter than those previously reported, these authors find that the magnetization breakdown is still limited by their pulse width (see the caption of their Fig. 4).
14. Zhen-Zhong Li, Solid State Theory (Advanced Education Press, Beijing, 1985).
15. 2.
16. Note that in Ni the optical absorption spectrum exhibits a big hump and no clear dominant transition can be seen [Handbook of Optical Constants of Solids, edited by E. D. Palik (Academic Press, Orlando, 1985)].
17. Here we do not include the magnetic field since it plays a significant role only on a much longer time scale than that we consider here. For the dynamics on a longer time scale, there have already been some investigations [see W. Hübner and K. H. Bennemann, Phys. Rev. B 53, 3422 (1996)].
18. On the ultrafast time scale, the electric field polarization plays a minor effect as observed experimentally [see E. Beaurepaire et al., Phys. Rev. B 58, 12 134 (1998)]. The role of SOC is blurred by the memory effect caused by the many-body interactions.
19. G. Baym, Lectures on Quantum Mechanism (W. A. Benjamin, Inc., New York, 1969).
20. B with a factor of 0.95.
21. There is a controversy among experimentalists on whether the change of the susceptibility tensor elements in the pump-probe SHG experiments reflects the change of the magnetization [see Ref. [3]; H. Regensburger, R. Vollmer, and J. Kirschner, Phys. Rev. B 61, 14 716 (2000); B. Koopmans et al., Phys. Rev. Lett. 85, 844 (2000)].
22. There is a controversy among experimentalists on whether the change of the susceptibility tensor elements in the pump-probe SHG experiments reflects the change of the magnetization [see Ref. [3]; H. Regensburger, R. Vollmer, and J. Kirschner, Phys. Rev. B 61, 14 716 (2000); B. Koopmans et al., Phys. Rev. Lett. 85, 844 (2000)].
23. Note that α is not exactly zero because the spin-orbit coupling already reduces the magnetic moment for the ground state as compared with the pure triplet T〉.
24. H. Petek et al. [Phys. Rev. Lett. 83, 832 (1999)] recently reported a very important observation. It is certainly of great interest to see whether one could induce the magnetization in noble metals. Our mechanism is a good starting point to study it theoretically since it contains some basic features of 3d metals. In particular, in a different topic one recent experiment [Bonn et al., Phys. Rev. B 61, 1101 (2000)] demonstrates a larger flexibility to investigate the electron-phonon coupling and hot electron transport, which clearly supports our theoretical strategy.
25. H. Petek et al. [Phys. Rev. Lett. 83, 832 (1999)] recently reported a very important observation. It is certainly of great interest to see whether one could induce the magnetization in noble metals. Our mechanism is a good starting point to study it theoretically since it contains some basic features of 3d metals. In particular, in a different topic one recent experiment [Bonn et al., Phys. Rev. B 61, 1101 (2000)] demonstrates a larger flexibility to investigate the electron-phonon coupling and hot electron transport, which clearly supports our theoretical strategy.
26. G. Ju et al., Phys. Rev. B 57, R700 (1998); P. F. Bennett et al., Opt. Lett. 24, 1373 (1999).
27. G. Ju et al., Phys. Rev. B 57, R700 (1998); P. F. Bennett et al., Opt. Lett. 24, 1373 (1999).