  Microscopy and diffraction measurements are presented of ultrathin binary
alloy films of ruthenium and molybdenum that are obtained by standard sputter
deposition. For compositions close to Ru50Mo50, we find the films to be
amorphous. The amorphicity of the films is accompanied by a significant
reduction of the roughness with respect to the roughness of equally thick films
of either ruthenium or molybdenum. We ascribe this to the absence of the grain
structure that is characteristic of the polycrystalline films of the separate
elements.
