  Depth resolved study of structural and magnetic profiles of
antiferromagnetic/ferromagnetic (AFM/FM) system upon annealing was performed in
this work. We studied systems comprising of AFM IrMn and FM (Co, Fe,
Co$_{70}$Fe$_{30}$) structures using polarized neutron and soft X-ray
scattering, secondary neutral spectrometry, and magnetometry. Structural depth
profiles obtained from neutron reflectometry indicate non-homogeneity of the
AFM layer even before annealing, which is associated with the migration of
manganese to the surface of the sample. Annealing of samples with CoFe and Co
layers leads to a slight increase ($\sim$ 5 %) in the migration of manganese,
which, however, does not lead to significant degradation of the exchange
coupling at the AFM/FM interface. A significantly different picture was
observed in the Fe/IrMn systems where a strong migration of iron into the AFM
layer was observed upon annealing of the sample, leading to erosion of the
magnetic profile, the formation of a non-magnetic alloy and degradation of the
pinning strength. This study can be useful in the design of AF/FM systems in
different spintronics devices, including HDD read heads, where thermal
annealing is applied at different stages of the device manufacturing process.
