Mixing and subsequent amorphization of ultrathin Ni81Fe19/Ta bilayers by 30Â keV Ni implantation

The ion implantation induced interfacial mixing and subsequent amorphization of ultrathin Ni81Fe19/Ta bilayers has been investigated by TRIDYN simulations and cross-sectional transmission electron microscopy. Due to the 30 keV Ni implantation the initially sharp interface between Ni81Fe19 and Ta broadens and an intermixing between both layers is observed. Consequently the Ni81Fe19 layer is increasingly doped with Ta in the interface near region. For the region exhibiting a Ta concentration above a threshold value irradiation induced amorphization takes place. For an increasing Ni implantation fluence this region is succeedingly enlarged. A quantitative agreement between simulations and experimental data is found.