  The domain state model for exchange bias has been further investigated by
considering vector spins for the antiferromagnet instead of Ising spins used in
the earlier studies. The qualitative results are similar to those with infinite
anisotropy for the antiferromagnet. However, under certain conditions softer
spins can lead to an even stronger bias field. The study shows a nontrivial
dependence of the exchange bias on the antiferromagnetic anisotropy.
