冒牌自然老師

Title: Femtomagnetism: Laser-induced femtosecond magnetization in ferromagnets
Time: 10/09/2009 (Fri.) 2:30 PM~3:30 PM
Place: RM 112, New Physics Building, NTU
Speaker: Prof. Guo-Ping Zhang, Physics Department, Indiana State University,
U. S. A.

Abstract:
Laser-induced femtosecond magnetism or femtomagnetism opens a new frontier for a faster magnetic storage device. This includes the inverse-Faraday writing/reading.  Probing such a fast magnetization change is a big challenge experimentally and theoretically. In this talk, I will first give an overview of this new field. Then, I will discuss (a) how the time-resolved magneto-optical Kerr effect is capable of detecting such a fast magnetization process; (b) the role played by the spin-orbit coupling and laser field; and (c) our current understanding of spin and orbital momenta within a two-level system. Both model results and first-principles results will be presented. Finally, I will present my own view of the direction of this field.

References:
(1) Zhang, G. P., W., Beaurepaire, E. Bigot, J.-Y. Laser-induced     
ultrafast demagnetization: Femtomagnetism, A new frontier?   Topics
Appl. Phys., 245-289 (2002).

(2) Zhang, G. P.  W.  Laser-induced ultrafast demagnetization
in ferromagnetic metals. Phys. Rev. Lett. , 3025-3028 (2000).

(3) Zhang, G. P. Laser-induced orbital and spin excitations in ferromagnets:
Insights from a two-level system. Phys. Rev. Lett.,
187203 (2008).

(4) G. P. Zhang, W. H, G. Lefkidis, Y. H. Bai, and Thomas F.
George, Nature Physics, 499 (2009).