Vibrational and electronic properties of a Cu90Nb10 nanocrystalline composite

The vibrational, electronic, and superconducting properties of a Cu₉₀Nb₁₀ nanocrystalline composite undergoing a transition from a coarse-grained state to a nanocrystalline state are investigated using neutron scattering and low-temperature heat capacity measurements. It is found that, compared to a coarse-grained sample, the nanocomposite is characterized by a higher density of low-frequency excitations and a decrease both in the density of states and in the superconducting transition temperature due to the size effect.