Exchange bias effects of NiFe/NiO bilayers through ion-beam bombardment on the NiO surface

The influence of ion-beam bombardment of the NiO surface on the exchange bias behavior of NiFe/NiO bilayers was systemically investigated with different bombardment energies and durations. The results show that by varying the bombardment energies, different crystallographic orientations are created which modifies the NiO spin structures. This results in the changes in the coupling type in NiO when it is in contact with the NiFe layer. The NiFe/NiO bilayers exhibited either enhanced or decreased exchange bias filed, depending on the uncompensated moments or misaligned NiO spin created by ion-beam bombardment. The variations in coercivities of NiFe/NiO bilayers imply that the NiO anisotropy could be tuned by ion-beam bombardment.

► The exchange bias behavior of NiFe/NiO bilayers was investigated.
► Uncompensated moments or misaligned NiO spins were created by ion-beam bombardment.
► The NiO anisotropy could be tuned by ion-beam bombardment.