Ion-beam mixing of Ni/Pd layers: I. Cascade mixing regime (low temperature)

A tomic mixing resulting from heavy-ion bombardment of thin-film Ni/Pd bilayers and thin Pd markers sandwiched between Ni layers has been investigated. Mixing experiments were performed over a temperature range 40–473 K, using 120 keV Ar⁺ and 145 keV Kr⁺ ions at a constant dose rate of 5.5 × 10¹² ions cm ⁻²s⁻¹ for doses up to 4 × 10¹⁶cm⁻². The resulting interdiffusion was measured, in situ, using Rutherford backscattering with 2−2.8 MeV ⁴He⁺ ions. The results showed that, for both markers and bilayers, the amount of mixing is similar for both configurations and varies linearly with the square root of the ion dose. Comparison of the induced mixing per ion, following irradiation at 40 K, shows that the mixing is dependent on the damage energy FD deposited at the interface region. The mixing is essentially athermal.