Chinese Acad Sci, Inst High Energy Phys, Synchrotron Radiat Lab, Beijing 100039, Peoples R China
Electronic structure of MBE-grown Co/Cu (111) films was studied by synchrotron radiation angular-resolved photoemission spectra and auger electron spectra during the process of growth and annealing. The experiment reveals that: the energy shift of s-d(z)(2)-hybridized band of copper increases with thickening of the coverage of cobalt, which proves that atomic intermixing occurrs at the interface, and there is mainly surface diffusion, not bulk interdiffusion during annealing. We attribute the diffusion in the two different processes to one driving force, i.e. the surface free energy of cobalt is remarkably larger than that of copper.