Time-resolved photo-magnetic switching of bubble domains in ferrimagnetic garnets

We investigate the single-domain switching of magnetization with a femtosecond laser pulse in Co-doped iron garnet films using time-resolved magneto-optical imaging. This switching regime is achieved with a pump fluence that is two times lower than the fluence required for multi-domain switching. We observed the picoseconds magnetization dynamics of switching in a single bubble domain with a diameter of a few micrometers by tuning the pump laser fluence. This may provide opportunities for cold photo-magnetic recording in magnetic bits approaching the nano-size scale.