Exchange bias in Fe_(x)Zn_(1-x)F_(2)/Co bilayers

摘要

The exchange bias (H_(E)) was measured in Fe_(x)Zn_(1-x)F_(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_(x)Zn_(1-x)F_(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.