Exchange bias in Fe _xZn _1-xF ₂/Co bilayers

Abstract

The exchange bias (H E) was measured in Fe xZn 1-xF 2/Co bilayers grown on MgO (100) with and without a 1.0 nm layer of pure FeF 2 at the interface between the Fe xZn 1-xF 2 and the Co layers. For x=0.83 samples with an additional 1.0 nm FeF 2 interface layer H E increases by 65% when compared to the FeF 2/Co bilayer. The FeF 2 interface layer also causes a significant H E to appear for x<0.5. This enhancement of H E with an FeF 2 interlayer cannot be explained by simply scaling the exchange bias with the Fe concentration. Presumably this is due to the formation of domain states inside the dilute antiferromagnetic film, and the pure interface layer increases the coupling between the ferromagnet and the antiferromagnet. © 2002 American Institute of Physics.