Nuclear-magnetic-resonance study of electronic structure in the copper-niobium superlattice

Cu nuclear-magnetic-resonance studies of a Cu/Nb superlattice reveal that the Cu in the superlattice is divided into at least two electronically distinct regions. One region has a small anisotropic Knight shift and a spin-lattice relaxation rate approximately 30% larger than ordinary Cu. The other region has large dipolar isotropic and anisotropic frequency shifts; its spin-lattice relaxation rate is up to two orders of magnitude smaller than that of ordinary Cu.