Field-ion microscopic observations showed that Pt adatoms replaced Ni(110) surface atoms at temperatures above 105K. The directions of the individual displacements in this replacement process were consistent with a model which involved the concerted motion of adatom and substrate atoms. The activation barrier to the exchange was estimated to be 0.28eV.

G.L.Kellogg: Physical Review Letters, 1991, 67[5], 216-9