Structural Stability of Stepped Nickel Surfaces

The structural stability of stepped Ni 755 and Ni 771 surfaces in the temperature range 20 500 degrees C and during adsorption of oxygen and different forms of carbon has been studied using scanning tunneling microscopy and low energy electron diffraction. A phase transition from the structure with double steps at room temperature to the structure with single steps at a temperature above 350 degrees C has been observed on the clean Ni 755 surface. This transition disappears after oxygen adsorption at a temperature above 350 degrees C. In this case, the structure on the Ni 755 surface with single steps is stabilized in contrast to Ni 771 , which tends to faceting during oxygen adsorption. It has been shown that fullerenes C 60 form an array of one dimensional chains at the upper boundaries of steps of the substrate, when they are adsorbed on the Ni 755 surfac