Single shot all optical switching of intrinsic micron size magnetic domains of a Pt/Co/Pt ferromagnetic stack

We demonstrate that magnetization reversal in a ferromagnetic Pt/Co/Pt stack can be induced by a single femtosecond laser pulse. We find that the size of the switched spot is comparable to the size of the intrinsic magnetic domains. It requires an absorbed energy density of ∼4 mJ cm−2, beyond which the excited spot fragments into a multidomain structure. The switching process can be toggled with sequential laser pulses and is helicity-independent. Furthermore, the dynamics of the magnetization reversal occurs in a timescale less than one microsecond. These results suggest that all-optical switching in ferromagnetic films requires that the laser spot matches with the specific domain sizes.