抄録
Femtosecond laser pulse induced magnetization reversal of α-Gd_23.1Fe_71.9Co_5.0 was investigated by time-resolved measurements of the polar Kerr-rotation.The dynamics is found to follow the Blochequation via a relaxation time that does not depend on temperature but strongly decreases with increasing excitation density.A minimum value of (190±40)ps was obtained for the highest applicable pump-fluence.Comparing the reversal dynamics to temperature induced variations of magnetization within a single domain state and to the magnetization dynamics measured in remanence, the different contributions of transient temperature and domain formation to the magnetic response are separated.
