Growth of Co and Fe on Cu(1 1 1): experiment and BFS based calculations

Abstract

The structure and morphology of Co and Fe films grown on Cu(1 1 1) have been investigated by thermal energy atom scattering (TEAS) and low-energy electron diffraction (LEED). It has been found that the growth mode of Co and Fe can be greatly improved by using Pb as surfactant, although in the case of Fe this works only for the first bilayer. This shows that the two systems exhibit decisive differences already in the first stages of the growth process. In a second series of experiments, the effect of codepositing Co–Cu and Fe–Cu on the films quality was investigated. The results are very promising, and suggest that very flat, structurally ordered fcc Fe–Cu and Co–Cu films can be prepared by applying this technique together with the use of Pb as surfactant. These results were complemented by atomistic simulations based on the BFS method for alloys. Simulations performed in the low-coverage regime suggest that the early stages of growth are governed to a great extent by the affinity of Cu for Co and Fe. We have also performed temperature-dependent Monte Carlo simulations to determine the structure of superlattices formed by codeposition of Cu–Co and Cu–Fe.