FIB induced structural modifications in thin magnetic films

Focused ion beam irradiation is a versatile tool that can be used for magnetic nanostructuring. In this work we compare both FIB irradiation and a standard implantation taking into account their distinctive irradiation features. A 50nm thick permalloy layer (Ni80Fe20) irradiated with different Ga+ ion fluences was used for the investigations. The structure was studied via XRD and EXAFS measurements carried out on the ESRF ROBL and ID01 facilities. Additionally TEM and magneto-optic Kerr effect magnetometry were performed. Both types of irradiation demonstrate a similar behaviour: increasing the ion fluence causes a further material crystallization and a decrease of the magnetic moment. However FIB irradiation leads to a stronger crystallite growth due to the high current densities used.