Oxidation of Gd–Ni composite and Gd cluster films grown on Ni(110) surface studied by photoemission

Soft X-ray synchrotron radiation photoemission (SRPES) and XPS were used to study the interaction of oxygen with Gd–Ni composite and Gd cluster films grown on Ni(110) surface. Different oxidation manners were found for the two kinds of films. Over the Gd–Ni composite film, the adsorption of oxygen resulted in the segregation and oxidation of Gd component, and chemisorbed O− and lattice oxygen were detected. For the Gd cluster film, with the increase of oxygen exposure the oxidation states of Gd were developed between the two peaks of the Gd4f double-peak at the expense of attenuation of HBE peak. Only one O1s XPS peak at 529.6 eV was detected in the range of 0–50 L exposure.