X-ray diffraction and NMR study on the structure of Co/Cu superlattices with artificially modified interfaces

An attempt has been made to clarify the effect of interfacial mixing on the x-ray diffraction (XRD) and ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$ NMR of magnetron-sputtered Co/Cu superlattices. Systematic and quantitative modification of interfaces have been achieved by codeposition of Co and Cu at interfaces. We show that high and low angle XRD patterns are not affected by the existence of compositionally mixed regions thinner than 0.3 nm, and that significant change in the distribution of the hyperfine field of ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$ is found. The interfacial modification by codeposition is a powerful method to investigate the interfacial effects on the properties of superlattices, since only the interfacial structures are modified, while the other structures remain unchanged.