Polarized neutron reflectometry study on a magnetic film with an ion beam imprinted stripe pattern

We used polarized neutron reflectometry for a quantitative study of the field dependent arrangement of the magnetization vector in the different regions of an ion beam imprinted stripe pattern in a magnetic film. For the magnetic patterning of the Co70Fe30 film we took advantage of the exchange bias to an antiferromagnetic Mn83Ir17 layer which was changed locally by He-ion bombardment. The exchange bias was set to be antiparallel in the two different striped regions. We found that after magnetization reversal of half of the stripes the magnetization in neighbouring regions is periodically canted with respect to the stripe axis so that the net magnetization of the ferromagnetic film turns almost perpendicular to the stripes. At the same time the projection of the magnetization vector onto the stripe axis has a periodically alternating sign.