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 dep ending upon film thickness and the sample temperature during depositio n. At growth temperatures below 270 K, three different superstructures are observed with increasing film thickness. These are a two dimensio nally 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) struc ture above 1.7 ML Mn. At growth temperatures above 270 K, Mn is incorp orated into the surface leading to the formation of an ordered alloy f ilm with c (2 X 2) structure. The maximum thickness of these epitaxial films with c(2 X 2) structure depends critically upon the growth temp erature. This shows the importance of kinetics for the growth of alloy films. Once the maximum thickness is exceeded, a variety of superstru ctures evolves due to the Mn excess at the surface.