STRUCTURE AND GROWTH OF MN ON NI(100)

The structure and growth of manganese on Ni(100) was studied using low-energy electron diffraction, medium-energy electron diffraction, and Auger-electron spectroscopy. A variety of superstructures is found depending upon film thickness and the sample temperature during deposition. At growth temperatures below 270 K, three different superstructures are observed with increasing film thickness. These are a two dimensionally disordered c (2 x 2) structure around 0.6 monolayer (ML) Mn, a c ( 10 X 2) structure between 0.9 and 1.7 ML Mn, and a c (12 X 8) structure above 1.7 ML Mn. At growth temperatures above 270 K, Mn is incorporated into the surface leading to the formation of an ordered alloy film with c (2 X 2) structure. The maximum thickness of these epitaxial films with c(2 X 2) structure depends critically upon the growth temperature. This shows the importance of kinetics for the growth of alloy films. Once the maximum thickness is exceeded, a variety of superstructures evolves due to the Mn excess at the surface.