Spin structure at the interface of exchange biased FeMn/Co bilayers

The origin of exchange biasing in FeMn/Co bilayers is elucidated using magn eto-optic Kerr effect and x-ray dichroism. It is found that the FeMn spin s tructure is aligned with the ferromagnetic (FM) moment of the Co layer, ind icating that "spin flop" coupling is not the mechanism for exchange bias in this system. Futhermore, the Fe forms an uncompensated surface. It is like ly that the FM Fe spins play a key role in the generation of the exchange b ias. These results provide new insight to the mechanism of exchange biasing in metallic ferromagnetic/antiferromagnetic systems.