Magnetic properties and structure of Gd-implanted L1 FePt thin films

In this study, we have investigated the effect of Gd implantation on composition, chemical order, and magnetic properties of 20 nm thick L10 ordered FePt thin films. We show that upon Gd implantation at 30 keV even a small amount of 1 at. % is sufficient to destroy the L10 order, resulting in a soft magnetic A1 FePt alloy, with the exception of a thin L10 ordered layer located at the film/substrate interface. Additionally, a strong resputter effect is observed which results in a large decrease in film thickness as well as to a reduction in Fe content in the FePt alloy. Post-annealing of samples in Ar atmosphere did not result in a restoration of the L10 order, but leads to a transformation to pure Pt and Fe2O3, facilitated by the presence of a high density of vacancies induced by the implantation process.