Ultrafast all-optical magnetization reversal in GdFeCo films around plasmonic nanostructures

Abstract

It has recently been experimentally demonstrated that reproducible and controllable all-optical magnetization reversal in GdFeCo films can be achieved with a single ultrafast (from 40fs to 3ps) femtosecond laser pulse. While the microscopic origin of the effect is still unclear, we suggest that the effect is caused by a combination of light-induced quasi-static magnetic field, with dynamic thermal effects due to laser heating, as well as magnetic fields generated by thermoelectric effect-caused electrical currents. This finding reveals great potential for ultrafast data storage through magnetic switching without the aid of an external magnetic field. It was further recently predicted that utilization of plasmonic nanostructures may provide the way to achieve fast all-optical magnetization switching with smaller/cheaper laser sources with longer pulse durations. We will present the simulations of temporal dynamics of magnetization reversal around plasmonic nanostructures with the combination of Landau Lifshitz Bloch and finite element modeling. Our modeling results predict that plasmonic nanostructures can significantly alter all-optical magnetization switching process and may help achieve a number of technologically important effects that cannot be achieved otherwise. Results of experimental studies of optical magnetization reversal in GdFeCo films around plasmonic nanostructures are also provided.