Patterning nucleation area by femtosecond laser in exchange-coupled systems

Optical control of the exchange bias field in IrMn/[Co/Pt]N heterostructures has been recently demonstrated. We show that this phenomenon can be used to create specific nucleation areas and even decide the preferential direction of propagation of the domain wall inside these preferred areas of nucleation. Using different features of a femtosecond laser, such as the helicity, fluence, and number of pulses, we designed robust patterns of various shapes and magnetic properties that can be host for domain wall propagation observations. Our finding provides an alternative method to already existing and time-consuming patterning methods.