Abstract

It has been shown more than ten years ago [1] that the magnetization of a ferromagnetic material can be modified and monitored using femtosecond optical pulses. This discovery has motivated many researches showing that the magnetization of materials can be controlled at the femtosecond time scale. The initial demagnetization, which occurs during the thermalization of the spins [2] (typically a few hundreds of femtoseconds) is not yet completely understood. In the present paper, we address the physical process of thermalization of the charges (time x_e) and the spins (time x_s), for several laser excitation and film thcknesses.

© 2009 IEEE