Increased exchange anisotropy due to disorder at permalloy/CoO interfaces

The exchange anisotropy of Ni80Fe20 (permalloy) films deposited onto bulk single crystal CoO substrates using molecular-beam epitaxy is strongly affected by the interface structure. Contrary to expectations for uncompensated interfaces, the loop shift increases for samples with greater interface disorder. The results are discussed in the light of proposed exchange anisotropy models. The results suggest that antiferromagnet domain dynamics are an important part of the exchange anisotropy mechanism.