Modification of the magnetic properties of exchange coupled NiFe/FeMn films by Ga+ ion irradiation

The influence of 30 keV Ga+ ion irradiation on the magnetic properties of polycrystalline NiFe/FeMn exchange bias layers were investigated. In this context, it was of particular interest to determine whether a previously observed enhancement of the bias field value for the irradiation with 5 keV He+ ions is a material-specific or an ion-specific effect. Moreover, the capability of magnetic micropatterning using Ga+ ions from a Focused Ion Beam source was tested. It could be demonstrated that magnetic patterning with a lower limit in the range of 100 – 1000 nm is possible.