Nonlocal ultrafast demagnetization dynamics of Co/Pt multilayers by optical field enhancement

The influence on ultrafast demagnetization dynamics of metallic nano-structured gratings deposited on thin films of magnetic Co/Pt multilayers is investigated by the time-resolved optical Kerr effect. Depending on the polarization of the pump pulse, a pronounced enhancement of the demagnetization amplitude is found. Calculation of the inhomogeneous optical field distribution due to plasmon interaction and time-dependent solutions of the coupled electron, lattice, and spin temperatures in two dimensions show good agreement with the experimental data, as well as giving evidence of non-local demagnetization dynamics due to electron diffusion.