Formation of a palladium carbide with a palladium-silicide-like structure in fullerene-C60/Pd multilayers

We present structural studies of C60/Pd multilayer films. A new phase of a layered structure with a sixfold (or threefold) axis, which is similar to the metastable phase in Pd–Si alloys, has been observed by means of transmission electron microscope and X-ray diffraction in the C60/Pd multilayer films after annealed at 470 K 60 min. This new phase, which is believed to be one metastable phase of Pd–C, is a hexagonal structure with the lattice constant a = 0.438 nm. The reciprocal lattice points become continuous spikes in the direction c∗ of the reciprocal lattice, which indicates the Pd–C phase consists of layers.