Understanding and controlling the magnetization dynamics on the femtosecond timescale is becoming essential both at the fundamental level and to develop future technological applications. While direct laser excitation of a ferromagnetic layer was commonly used during the past twenty years, laser induced hot-electrons femtosecond pulses and subsequent transport in magnetic multilayers has recently attracted a lot of attention. Indeed, replacing photons by hot-electrons offers complementary information to improve our understanding of ultrafast magnetization dynamics and to provide new possibilities for manipulating the magnetization in a thin magnetic heterostructure on the femtosecond timescale.
In this talk, I will focus on the generation and transport of hot-electrons following femtosecond laser pulse excitation. I will discuss their role in the ultrafast loss of magnetization in magnetic multilayers. I will show that hot electrons can induce an ultrafast magnetization reversal in ferrimagnetic GdFeCo alloy. Moreover, these ultrafast currents can be spin-polarized, allowing for sub-ps all-optical control of magnetization in magnetic multilayers.