COMPOSITIONAL OSCILLATIONS AND STRAIN EFFECTS AT THE ANNEALED CO PD(100) INTERFACE - A STUDY BY X-RAY PHOTOELECTRON DIFFRACTION AND LOW-ENERGY ION-SCATTERING/

The properties of the interface obtained by cobalt deposition on the P d(100) surface and successive annealing have been studied by X-ray pho toelectron diffraction (XPD) and low energy ion scattering (LEIS). The ''as deposited'' cobalt layer shows considerable lattice strain (abou t 10%) for coverages up to approximately 20-monolayer equivalents. Ann ealing at temperatures of the order of 700 K leads to intermixing with the formation of a surface alloy and the partial release of the strai n. The combination of LEIS and XPD measurements shows that cobalt in t he surface phase is preferentially located in the second outermost lay er from the surface.