Abstract: Co-doped NiO inhomogeneous films were synthesized by sputtering metallic Co chips and NiO togetherand the exchange bias of Co-doped NiO/FeNi bilayers was investigated. When Co content was up to 25.2％, the exchange bias field H_E of Co-doped NiO/FeNi bilayer at room temperature increased to the maximumwhich was about three times that of the undoped-bilayer. Analysis suggests that the nanometer-sized Co-metal clusters enchased in NiO matrix played an important role in the change of magnetic behavior for the bilayers.

Key words: Co\|doped NiO/FeNi bilayer, exchange bias, cluster