X-ray photoemission spectroscopy studies of cerium thin films on transition-metal foils: Ce/Re, Ce/Ir, and Ce/Pt

Abstract

We report x-ray photoemission spectroscopy studies of the growth of ultrathin (0.1--5 monolayers) cerium films on polycrystalline rhenium, iridium, and platinum substrates. Our data indicate that Ce grows on Re without intermixing or compound formation, that on Pt reaction (i.e., compound formation) as well as interdiffusion is strong, while on Ir compound formation occurs but interdiffusion is weaker than for Pt. At low coverages the Ce has identical 3d binding energy and is trivalent for all three substrates and there appears to be a threshold for the onset of mixed-valence behavior.