  In the investigations of antiferromagnetic (AF)/ ferromagnetic (FM) bilayer
samples, often distinct experimental techniques yield different values for the
measured exchange anisotropy field (HE). Using a simple microscopic model for
representing the AF/FM interface, which incorporates the effect of interface
roughness, we propose that the observed discrepancy may be accounted for by the
dependence of the interface energy between the AF and FM layers with the value
of the external applied field (H) as recently observed in anisotropic
magnetoresistance measurements, lending support to our proposal.
