Increase in ferromagnetic/antiferromagnetic exchange bias due to a reduction of the interfacial exchange interaction

The effect of the location of nonmagnetic impurities (Au) inserted in the NiO layer of NiO/Co bilayers on the exchange bias was experimentally investigated. The inserted Au layer consists of a discontinuous plane of Au islands. The experiments were interpreted in terms of a reduced dragging of the NiO magnetization during Co magnetization reversal. An initial increase in the exchange bias field is observed when the Au layer is introduced at the Co/NiO interface.