Ion scattering studies of ordered alloy surfaces: CuAu(100) and NiAl

The composition and structure of ahoy surfaces can differ from the correspo nding bulk properties due to segregation and relaxation effects. We studied the (1 0 0) surface of the ordered alloy CuAu and amorphous Ni and Al by l ow-energy Ne+ and Nat ion scattering. The interpretation of the experimenta l results is supported by numerical simulations using the MARLOWE code. In the CuAu system a certain geometry was found to be very sensitive to Au pre sence in the 2nd layer. Comparison with MARLOWE results also allows to stud y variations in the ion yields arising from neutralization effects. By traj ectory analysis ion survival probabilities are estimated for Ni and Al. (C) 2000 Elsevier Science B.V. All rights reserved.