  The effect of nonmagnetic metal additives in metallic antiferromagnets (AFMs)
on the exchange bias (EB) has been investigated from a structural, magnetic and
Monte Carlo simulation point of view in bilayers of CoFe/IrMn:Cu. Dilution by
Cu atoms throughout the volume of the AFM IrMn give rise to an enhanced EB
field for temperatures between 5 K and 300 K. The thermoremanent magnetization
of the AFM-only is also enhanced with dilution, shows qualitatively the same
temperature dependence as EB field and is at the origin of the EB mechanism.
Monte Carlo simulations based on a Heisenberg model and temperature dependent
uncompensated AFM moments confirm well the experimental results.
