Epitaxial growth of body-centered-cubic nickel on iron

Abstract

Studies by low-energy electron diffraction (LEED) and Auger electron spectroscopy of nickel films grown in ultra-high vacuum onto a clean Fe{001} surface show that the films have the body-centered cubic structure with the same lattice constant and the same multilayer relaxation as the clean substrate, as long as they are thinner than about 6 layers. LEED intensity analyses show that the multilayer relaxation of both clean Fe{001} and 3-layer thick Ni films involves 5% contraction of the first and 5% expansion of the second interlayer spacing. These new values of the multilayer relaxation of clean Fe{001} represent an improvement over previous determinations. Thicker Ni films, up to 100 layers, have a complicated structure that is neither b.c.c. nor f.c.c. Short anneals at temperatures between 200 and 650°C cause rapid diffusion of Ni into the Fe substrate with little evidence for formation of the stable f.c.c. phase of Ni.