Partial magnetization reversal using laser annealing in patterned NiFe/FeMn film

We have studied local magnetization reversal by laserannealing in exchange biased NiFe/FeMn bilayer. Localmagnetization reversal was performed by using the Nd:YAG laserunder external magnetic field. When the laser illuminated thepatterned film with the power of above 300 mW during 15 min, amagnetoresistance (MR) curve with symmetric peaks at the oppositefield was obtained due to the local reversal of exchange biasing.A similar result was observed in NiFe/FeMn/NiFe trilayer. As theexposed area expanded, the intensity of opposite MR peakincreased. The direction of exchange anisotropy in the partiallyreversed region can be restored by local laser annealing underalternating magnetic field, even if its MR peak was reduced by thedamage and interdiffusion. The magnetic new domain structures ofthe partially reversed region was generated by laser annealingnear the exposed area.