Atomic processes in self-diffusion of Ni surfaces

Using a field ion microscope, we have probed the diffusion behavior of Ni adatoms on Ni surfaces. Activation barrier heights have been derived to be 0.22±0.02 eV and 0.59±0.03 eV for self-diffusion on Ni(111) and Ni(001), and 0.84±0.19 eV for the `ascending' motion of Ni(111) step edge atoms. From the visit site maps, we have experimentally determined the mechanism of self-diffusion on Ni(001) surfaces to be atomic exchange.