Ion bombardment induced and thermal induced atomic exchanges: Ni, Fe, and Co Adatoms on the Ir(001) surface

The temperature dependent behavior of Ni, Fe, and Co adatoms on the (1 × 1) and (5 × 1) Ir(001) surfaces have been studied using low energy helium ion scattering. Ni, Fe, and Co atoms were deposited on well cleaned and treated surfaces kept at 110 K. For the (1 × 1) surface, the ion bombardment induces a continuous exchange of adatoms with substrate atoms. In addition, rapid rises in the Ir signal intensities are found when the surface temperature is gradually raised to 200, 180, and 180 K which mark the onset of a thermally induced atomic exchange between Ni, Fe, and Co adatoms and substrate Ir atoms, respectively. For the (5 × 1) surface, no such exchanges are obvious.