The effect of the sputtering gas (Ar, Xe) on FePt clusters formation. Structural and magnetic properties

In this study it will be reported about the effect of the sputtering gases, Ar and Xe, on FePt clusters formation using magnetron sputtering deposition at high working pressures. Two different deposition techniques were investigated, a sequential layer by layer deposition and a co-deposition of Fe and Pt. All layers with bulk equivalent thicknesses between 3 to 5 nm were realized at RT and subsequently rapid thermal annealed in order to induce the A1-L10 ordering transformation at 550°C.
The highest L10 fraction in the annealed samples was found using Xe as sputtering gas: Xe decreases the transformation activation energy and therefore, reduces the critical thickness necessary to obtain the strong ferromagnetic phase.
The Ar assisted depositions give FePt clusters with the L10 phase only if the layer-by-layer growth is used, whereas for Xe no differences in the deposition techniques were observed.