Temperature-dependent intermixing of ultrathin Co films grown on Cu(1Â 0Â 0)

The growth and chemical composition of Co on Cu(1 0 0) has been studied by He ion scattering and Auger electron spectroscopy (AES) at different temperatures (T = 130 K, T = 300 K and T = 410 K). Based on different information depths for electron-induced Cu-MNN and Cu-LMM Auger signals and inner shell production by grazingly scattered protons restricted to the topmost layer, we have modeled the Auger data in order to obtain quantitative information on the chemical composition of ultrathin intermixed Co-Cu films. We find that intermixing and Cu diffusion is not only important for film growth at elevated temperatures, but also for heterogeneous Co/Cu epitaxy at room temperature.