64Ni implantation in 57Fe thin films studied by RBS and CEMS techniques

Thin films of 57Fe deposited on SiO2 substrates were implanted with 0.5, 2.5, 5 and 10 × 101664Ni/cm2. The implantation energy (80 keV) was calculated to alter the whole thickness (70 nm) of the samples. The 64Ni isotope was chosen for its good mass separation with 57Fe in the backscattering spectroscopy measurements (RBS) at 5.7 MeV α-particles. Thus the RBS technique was used to determine the nickel depth profiles in the implanted surface. Due to the high sputtering yield ( YNi/Fe ≈ 2), saturation is nearly reached for the highest implanted fluence. Conversion electron Mossbauer spectroscopy (CEMS) was used to identify various products of implantation. FeNi alloys with different compositions and structures are formed: Fe(Ni) solid solution, bcc Fe-rich phase, fcc Ni-rich zone and fcc FeNi Invar alloys.