Optical creation and annihilation of skyrmion patches in a chiral magnet

A key challenge for the realization of future skyrmion devices comprises the controlled creation, annihilation, and detection of these topologically nontrivial magnetic textures. In this study, we report an all-optical approach for writing, deleting, and reading skyrmions in the chiral magnet Fe0.75Co0.25Si based on thermal quenching. Using focused femtosecond laser pulses, patches of a thermally metastable skyrmion lattice state are created and annihilated locally, demonstrating unprecedented control of skyrmions in chiral magnets. The skyrmion state is read out by analyzing the microwave spin excitations in time-resolved magneto-optical Kerr effect measurements. Extracting the magnetic field and laser-fluence dependence, we find well-separated magnetic field regimes and different laser-fluence thresholds for the laser-induced creation and annihilation of skyrmions. The all-optical skyrmion control, as established in this study for a model system, represents a promising and energy-efficient approach for the realization of skyrmions as magnetic bits in future storage devices, reminiscent of magneto-optical storage devices in the past.