Share Email Print
cover

Proceedings Paper

Ultrafast dynamics of spin waves and coercivity of a FePt/FeNi exchange coupling film studied by femtosecond laser Kerr spectroscopy
Author(s): Shufa Li; Zhifeng Chen; Chuyuan Cheng; Jiaming Li; Shiming Zhou; Tianshu Lai
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Ultrafast dynamics of spin waves and coercivity of a FePt/FeNi exchange coupling film is studied by femtosecond laser Kerr spectroscopy. Magnetization-precession spin waves are observed. Time-delayed magneto-optical Kerr hysteresis loop (TDMOKHL) technique is used to study the dynamics of coercivity of the magnetic film under laser excitations as done usually. However, we find that the dynamics of coercivity revealed by TDMOKHL technique does not reflect the evolution of initial coercivity given by the initial hysteresis loop with no pump excitation, but does that of final coercivity under laser excitation. The final coercivity is given by the hysteresis loop measured at a negative pump-probe delay time under pump excitation. The evolution of initial coercivity can be observed only under a weak pump excitation in which magnetic system behaves reversible magnetically. In general, TDMOKHL technique can not track the evolution of coercivity of a magnetic system because TDMOKHLs do not reflect the time evolution of initial hysteresis loop with no laser excitation. The correctness of all previous reports on the dynamics of coercivity and magnetic-order transition of a laser-excited magnetic system needs reexamining if those reports were dependent on TDMOKHL technique. The oscillatory recovery behavior of final coercivity is observed under pump excitation and ascribed to metastability of zero magnetization state.

Paper Details

Date Published: 24 January 2013
PDF: 7 pages
Proc. SPIE 8782, 2012 International Workshop on Information Storage and Ninth International Symposium on Optical Storage, 87820Q (24 January 2013); doi: 10.1117/12.2016670
Show Author Affiliations
Shufa Li, Sun Yat-Sen Univ. (China)
Zhifeng Chen, Sun Yat-Sen Univ. (China)
Chuyuan Cheng, Sun Yat-Sen Univ. (China)
Jiaming Li, Sun Yat-Sen Univ. (China)
Shiming Zhou, Tongji Univ. (China)
Tianshu Lai, Sun Yat-Sen Univ. (China)


Published in SPIE Proceedings Vol. 8782:
2012 International Workshop on Information Storage and Ninth International Symposium on Optical Storage
Fuxi Gan; Zhitang Song, Editor(s)

© SPIE. Terms of Use
Back to Top