Athermal All-Optical Femtosecond Magnetization Reversal in GdFeCo

Abstract

Magnetization reversal in GdFeCo by circularly polarized light is shown to occur at the femtosecond time scale. In contrast to the well known laser-assisted magnetization reversal based on the laser heating, we here demonstrate that this femtosecond all-optical magnetization reversal is more efficient at lower temperatures. The lower the temperatures, the smaller the laser fluence required for the switching. This switching is in agreement with a more recent theoretical prediction $[ \text{Phys. Lett. A \textbf{372}, 1915 (2008)} ] $ and demonstrates the feasibility of the femtosecond athermal magnetization reversal.