Light induced ultrafast magnetization dynamics in metallic compounds.

We review the phenomenology of light-induced ultrafast magnetization dynamics, with emphasis on metallic compounds. The interaction of femtosecond laser pulses with magnetic thin films induces a wide range of out of equilibrium phenomena, leading to an ultrafast demagnetization, and a subsequent magnetization dynamics. The latter can lead to a deterministic reversal of the magnetization or allow for the controlled motion of domain walls. Those light-induced magnetization manipulations have potential application for ultrafast and energy efficient spintronic. The review summarizes experimental results and theoretical approaches on demagnetization and the all-optical helicity-dependent switching of the magnetization, whose underlying mechanism(s) are still heavily debated, even after 25 years of intensive research. • The magnetic excitations responsible for the ultrafast demagnetization are debated. • A broad overview of the mechanisms through which they could be generated is provided. • Criteria allowing for the helicity-dependent all-optical switching are reviewed. • The origin of the helicity-dependence is examined. [ABSTRACT FROM AUTHOR]