Tuning exchange bias in Ni/FeF2 heterostructures using antidot arrays

The transition from positive to negative exchange bias can be systematically tuned with antidot arrays artificially introduced into Ni/FeF2 ferromagnetic/antiferromagnetic heterostructures. These results are a consequence of the energy balance and suggest that the nanostructure plays a key role in the formation of pinned uncompensated spin regions in the antiferromagnetic FeF2 layer. These noninterfacial magnetic moments created at the antidot faces favor the onset of positive exchange bias at lower cooling fields. (C) 2009 American Institute of Physics. [doi:10.1063/1.3248306]